Parthanatos and its associated components: Promising therapeutic targets for cancer

Current insights on mitochondria-associated endoplasmic reticulum membranes (MAMs) and their significance in the pathophysiology of ocular disorders

The intricate interaction network necessary for essential physiological functions underscores the interdependence among eukaryotic cells. Mitochondria-Associated Endoplasmic Reticulum Membranes (MAMs), specialized junctions between mitochondria and the ER, were recently discovered. These junctions participate in various cellular processes, including calcium level regulation, lipid metabolism, mitochondrial integrity maintenance, autophagy, and inflammatory responses via modulating the structure and molecular composition of various cellular components. Therefore, MAMs contribute to the pathophysiology of numerous ocular disorders, including Diabetic Retinopathy (DR), Age-related Macular Degeneration (AMD) and glaucoma. In addition to providing a concise overview of the architectural and functional aspects of MAMs, this review explores the key pathogenetic pathways involving MAMs in the development of several ocular disorders.

Parthanatos: Mechanisms, modulation, and therapeutic prospects in neurodegenerative disease and stroke

Parthanatos is a cell death signaling pathway that has emerged as a compelling target for pharmaceutical intervention. It plays a pivotal role in the neuron loss and neuroinflammation that occurs in Parkinson's Disease (PD), Alzheimer's Disease (AD), Huntington's Disease (HD), Amyotrophic Lateral Sclerosis (ALS), and stroke. There are currently no treatments available to humans to prevent cell death in any of these diseases. This review provides an in-depth examination of the current understanding of the Parthanatos mechanism, with a particular focus on its implications in neuroinflammation and various diseases discussed herein. Furthermore, we thoroughly review potential intervention targets within the Parthanatos pathway. We dissect recent progress in inhibitory strategies, complimented by a detailed structural analysis of key Parthanatos executioners, PARP-1, AIF, and MIF, along with an assessment of their established inhibitors. We hope to introduce a new perspective on the feasibility of targeting components within the Parthanatos pathway, emphasizing its potential to bring about transformative outcomes in therapeutic interventions. By delineating therapeutic opportunities and known targets, we seek to emphasize the imperative of blocking Parthanatos as a precursor to developing disease-modifying treatments. This comprehensive exploration aims to catalyze a paradigm shift in our understanding of potential neurodegenerative disease therapeutics, advocating for the pursuit of effective interventions centered around Parthanatos inhibition.

Donafenib inhibits PARP1 expression and induces DNA damage, in combination with PARP1 inhibitors promotes apoptosis in liver cancer cells

Liver cancer is a prevalent malignant tumor globally. The newly approved first-line drug, donafenib, is a novel oral small molecule multi-tyrosine kinase inhibitor that has significant antitumor effects on liver cancer. This study aims to investigate the antitumor effects of donafenib on liver cancer and to explore its potential mechanisms. Donafenib significantly inhibited the viability of Huh-7 and HCCLM3 cells, inhibited malignant cell proliferation, and promoted cell apoptosis, as demonstrated by CCK-8, EdU, and Calcein/PI (propidium iodide) staining experiments. The results of DNA damage detection experiments and western blot analysis indicate that donafenib caused considerable DNA damage in liver cancer cells. The analysis of poly (ADP-ribose) polymerase 1 (PARP1) in liver cancer patients using online bioinformatics data websites such as TIMER2.0, GEPIA, UALCAN, cBioPortal, Kaplan-Meier Plotter, and HPA revealed a high expression of PARP1, which is associated with poor prognosis. Molecular docking and western blot analysis demonstrated that donafenib can directly target and downregulate the protein expression of PARP1, a DNA damage repair protein, thereby promoting DNA damage in liver cancer cells. Western blot and immunofluorescence detection showed that the group treated with donafenib combined with PARP1 inhibitor had significantly higher expression of γ-H2AX and 8-OHdG compared to the groups treated with donafenib or PARP1 inhibitors alone, the combined treatment suppresses the expression of the antiapoptotic protein Bcl2 and enhances the protein expression level of the proapoptotic protein Bcl-2-associated X protein (BAX). These data suggest that the combination of donafenib and a PARP1 inhibitor results in more significant DNA damage in cells and promotes cell apoptosis. Thus, the combination of donafenib and PARP1 inhibitors has the potential to be a treatment option for liver cancer.

Non-apoptotic cell death in osteoarthritis: Recent advances and future

Osteoarthritis (OA) is the most common degenerative joint disease. Multiple tissues are altered during the development of OA, resulting in joint pain and permanent damage to the osteoarticular joints. Current research has demonstrated that non-apoptotic cell death plays a crucial role in OA. With the continuous development of targeted therapies, non-apoptotic cell death has shown great potential in the prevention and treatment of OA. We systematically reviewed research progress on the role of non-apoptotic cell death in the pathogenesis, development, and outcome of OA, including autophagy, pyroptosis, ferroptosis, necroptosis, immunogenic cell death, and parthanatos. This article reviews the mechanism of non-apoptotic cell death in OA and provides a theoretical basis for the identification of new targets for OA treatment.

Unveiling the impact of cell death-related genes and immune dynamics on drug resistance in lung adenocarcinoma: a risk score model and functional insights

Lung adenocarcinoma (LUAD), characterized by its heterogeneity and complex pathogenesis, is the focus of this study which investigates the association between cell death-related genes and LUAD. Through machine learning, a risk score model was developed using the Coxboost rsf algorithm, demonstrating strong prognostic accuracy in both validation (GSE30219, GSE31210, GSE72094) and training (TCGA-LUAD) datasets with C-indices of 0.93, 0.67, 0.68, and 0.64, respectively. The study reveals that the expression of Keratin 18 (KRT18), a key cytoskeletal protein, varies across LUAD cell lines (DV-90, PC-9, A549) compared to normal bronchial epithelial cells (BEAS-2B), suggesting its potential role in LUAD's pathogenesis. Kaplan-Meier survival curves further validate the model, indicating longer survival in the low-risk group. A comprehensive analysis of gene expression, functional differences, immune infiltration, and mutations underscores significant variations between risk groups, highlighting the high-risk group's immunological dysfunction. This points to a more intricate tumor immune environment and the possibility of alternative therapeutic strategies. The study also delves into drug sensitivity, showing distinct responses between risk groups, underscoring the importance of risk stratification in treatment decisions for LUAD patients. Additionally, it explores KRT18's epigenetic regulation and its correlation with immune cell infiltration and immune regulatory molecules, suggesting KRT18's significant role in the tumor immune landscape. This research not only offers a valuable prognostic tool for LUAD but also illuminates the complex interplay between cell death-related genes, drug sensitivity, and immune infiltration, positioning KRT18 as a potential therapeutic or prognostic target to improve patient outcomes by personalizing LUAD treatment strategies.

Prognostic and immunological implications of heterogeneous cell death patterns in prostate cancer

BACKGROUND

Prostate cancer is one of the most common cancers in men with a significant proportion of patients developing biochemical recurrence (BCR) after treatment. Programmed cell death (PCD) mechanisms are known to play critical roles in tumor progression and can potentially serve as prognostic and therapeutic biomarkers in PCa. This study aimed to develop a prognostic signature for BCR in PCa using PCD-related genes.

MATERIALS AND METHODS

We conducted an analysis of 19 different modes of PCD to develop a comprehensive model. Bulk transcriptomic, single-cell transcriptomic, genomic, and clinical data were collected from multiple cohorts, including TCGA-PRAD, GSE58812, METABRIC, GSE21653, and GSE193337. We analyzed the expression and mutations of the 19 PCD modes and constructed, evaluated, and validated the model.

RESULTS

Ten PCD modes were found to be associated with BCR in PCa, with specific PCD patterns exhibited by various cell components within the tumor microenvironment. Through Lasso Cox regression analysis, we established a Programmed Cell Death Index (PCDI) utilizing an 11-gene signature. High PCDI values were validated in five independent datasets and were found to be associated with an increased risk of BCR in PCa patients. Notably, older age and advanced T and N staging were associated with higher PCDI values. By combining PCDI with T staging, we constructed a nomogram with enhanced predictive performance. Additionally, high PCDI values were significantly correlated with decreased drug sensitivity, including drugs such as Docetaxel and Methotrexate. Patients with lower PCDI values demonstrated higher immunophenoscores (IPS), suggesting a potentially higher response rate to immune therapy. Furthermore, PCDI was associated with immune checkpoint genes and key components of the tumor microenvironment, including macrophages, T cells, and NK cells. Finally, clinical specimens validated the differential expression of PCDI-related PCDRGs at both the gene and protein levels.

CONCLUSION

In conclusion, we developed a novel PCD-based prognostic feature that successfully predicted BCR in PCa patients and provided insights into drug sensitivity and potential response to immune therapy. These findings have significant clinical implications for the treatment of PCa.

Programmed cell death in hepatocellular carcinoma: mechanisms and therapeutic prospects

Hepatocellular Carcinoma (HCC), the most common primary liver cancer, ranks as the third most common cause of cancer-related deaths globally. A deeper understanding of the cell death mechanisms in HCC is essential for developing more effective treatment strategies. This review explores programmed cell death (PCD) pathways involved in HCC, including apoptosis, necroptosis, pyroptosis, ferroptosis, and immunogenic cell death (ICD). These mechanisms trigger specific cell death cascades that influence the development and progression of HCC. Although multiple PCD pathways are involved in HCC, shared cellular factors suggest a possible interplay between the different forms of cell death. However, the exact roles of different cell death pathways in HCC and which cell death pathway plays a major role remain unclear. This review also highlights how disruptions in cell death pathways are related to drug resistance in cancer therapy, promoting a combined approach of cell death induction and anti-tumor treatment to enhance therapeutic efficacy. Further research is required to unravel the complex interplay between cell death modalities in HCC, which may lead to innovative therapeutic breakthroughs.

Unveiling the hidden dangers: a review of non-apoptotic programmed cell death in anesthetic-induced developmental neurotoxicity

Anesthetic-induced developmental neurotoxicity (AIDN) can arise due to various factors, among which aberrant nerve cell death is a prominent risk factor. Animal studies have reported that repeated or prolonged anesthetic exposure can cause significant neuroapoptosis in the developing brain. Lately, non-apoptotic programmed cell deaths (PCDs), characterized by inflammation and oxidative stress, have gained increasing attention. Substantial evidence suggests that non-apoptotic PCDs are essential for neuronal cell death in AIDN compared to apoptosis. This article examines relevant publications in the PubMed database until April 2024. Only original articles in English that investigated the potential manifestations of non-apoptotic PCD in AIDN were analysed. Specifically, it investigates necroptosis, pyroptosis, ferroptosis, and parthanatos, elucidating the signaling mechanisms associated with each form. Furthermore, this study explores the potential relevance of these non-apoptotic PCDs pathways to the pathological mechanisms underlying AIDN, drawing upon their distinctive characteristics. Despite the considerable challenges involved in translating fundamental scientific knowledge into clinical therapeutic interventions, this comprehensive review offers a theoretical foundation for developing innovative preventive and treatment strategies targeting non-apoptotic PCDs in the context of AIDN.

PARP1 inhibition prevents oxidative stress in age-related hearing loss via PAR-Ca2+-AIF axis in cochlear strial marginal cells

Studies have highlighted oxidative damage in the inner ear as a critical pathological basis for sensorineural hearing loss, especially the presbycusis. Poly(ADP-ribose) polymerase-1 (PARP1) activation responds to oxidative stress-induced DNA damage with pro-repair and pro-death effects resembling two sides of the same coin. PARP1-related cell death, known as parthanatos, whose underlying mechanisms are attractive research hotspots but remain to be clarified. In this study, we observed that aged rats showed stria vascularis degeneration and oxidative damage, and PARP1-dependent cell death was prominent in age-related cochlear disorganization and dysfunction. Based on oxidative stress model of primary cultured stria marginal cells (MCs), we revealed that upregulated PARP1 and PAR (Poly(ADP-ribose)) polymers are responsible for MCs oxidative death with high mitochondrial permeability transition pore (mPTP) opening and mitochondrial membrane potential (MMP) collapse, while inhibition of PARP1 ameliorated the adverse outcomes. Importantly, the PARylation of apoptosis-inducing factor (AIF) is essential for its conformational change and translocation, which subsequently causes DNA break and cell death. Concretely, the interaction of PAR and truncated AIF (tAIF) is the mainstream in the parthanatos pathway. We also found that the effects of AIF cleavage and release were achieved through calpain activity and mPTP opening, both of which could be regulated by PARP1 via mediation of mitochondria Ca2+ concentration. In conclusion, the PAR-Ca2+-tAIF signaling pathway in parthanatos contributes to the oxidative stress damage observed in MCs. Targeting PAR-Ca2+-tAIF might be a potential therapeutic strategy for the early intervention of presbycusis and other oxidative stress-associated sensorineural deafness.

N-Myristoytransferase Inhibition Causes Mitochondrial Iron Overload and Parthanatos in TIM17A-Dependent Aggressive Lung Carcinoma

Myristoylation is a type of protein acylation by which the fatty acid myristate is added to the N-terminus of target proteins, a process mediated by N-myristoyltransferases (NMT). Myristoylation is emerging as a promising cancer therapeutic target; however, the molecular determinants of sensitivity to NMT inhibition or the mechanism by which it induces cancer cell death are not completely understood. We report that NMTs are a novel therapeutic target in lung carcinoma cells with LKB1 and/or KEAP1 mutations in a KRAS-mutant background. Inhibition of myristoylation decreases cell viability in vitro and tumor growth in vivo. Inhibition of myristoylation causes mitochondrial ferrous iron overload, oxidative stress, elevated protein poly (ADP)-ribosylation, and death by parthanatos. Furthermore, NMT inhibitors sensitized lung carcinoma cells to platinum-based chemotherapy. Unexpectedly, the mitochondrial transporter translocase of inner mitochondrial membrane 17 homolog A (TIM17A) is a critical target of myristoylation inhibitors in these cells. TIM17A silencing recapitulated the effects of NMT inhibition at inducing mitochondrial ferrous iron overload and parthanatos. Furthermore, sensitivity of lung carcinoma cells to myristoylation inhibition correlated with their dependency on TIM17A. This study reveals the unexpected connection between protein myristoylation, the mitochondrial import machinery, and iron homeostasis. It also uncovers myristoylation inhibitors as novel inducers of parthanatos in cancer, and the novel axis NMT-TIM17A as a potential therapeutic target in highly aggressive lung carcinomas.

SIGNIFICANCE

KRAS-mutant lung carcinomas with LKB1 and/or KEAP1 co-mutations have intrinsic therapeutic resistance. We show that these tumors are sensitive to NMT inhibitors, which slow tumor growth in vivo and sensitize cells to platinum-based chemotherapy in vitro. Inhibition of myristoylation causes death by parthanatos and thus has the potential to kill apoptosis and ferroptosis-resistant cancer cells. Our findings warrant investigation of NMT as a therapeutic target in highly aggressive lung carcinomas.

A novel prognostic signature related to programmed cell death in osteosarcoma

Background

Osteosarcoma primarily affects children and adolescents, with current clinical treatments often resulting in poor prognosis. There has been growing evidence linking programmed cell death (PCD) to the occurrence and progression of tumors. This study aims to enhance the accuracy of OS prognosis assessment by identifying PCD-related prognostic risk genes, constructing a PCD-based OS prognostic risk model, and characterizing the function of genes within this model.

Method

We retrieved osteosarcoma patient samples from TARGET and GEO databases, and manually curated literature to summarize 15 forms of programmed cell death. We collated 1621 PCD genes from literature sources as well as databases such as KEGG and GSEA. To construct our model, we integrated ten machine learning methods including Enet, Ridge, RSF, CoxBoost, plsRcox, survivalSVM, Lasso, SuperPC, StepCox, and GBM. The optimal model was chosen based on the average C-index, and named Osteosarcoma Programmed Cell Death Score (OS-PCDS). To validate the predictive performance of our model across different datasets, we employed three independent GEO validation sets. Moreover, we assessed mRNA and protein expression levels of the genes included in our model, and investigated their impact on proliferation, migration, and apoptosis of osteosarcoma cells by gene knockdown experiments.

Result

In our extensive analysis, we identified 30 prognostic risk genes associated with programmed cell death (PCD) in osteosarcoma (OS). To assess the predictive power of these genes, we computed the C-index for various combinations. The model that employed the random survival forest (RSF) algorithm demonstrated superior predictive performance, significantly outperforming traditional approaches. This optimal model included five key genes: MTM1, MLH1, CLTCL1, EDIL3, and SQLE. To validate the relevance of these genes, we analyzed their mRNA and protein expression levels, revealing significant disparities between osteosarcoma cells and normal tissue cells. Specifically, the expression levels of these genes were markedly altered in OS cells, suggesting their critical role in tumor progression. Further functional validation was performed through gene knockdown experiments in U2OS cells. Knockdown of three of these genes-CLTCL1, EDIL3, and SQLE-resulted in substantial changes in proliferation rate, migration capacity, and apoptosis rate of osteosarcoma cells. These findings underscore the pivotal roles of these genes in the pathophysiology of osteosarcoma and highlight their potential as therapeutic targets.

Conclusion

The five genes constituting the OS-PCDS model-CLTCL1, MTM1, MLH1, EDIL3, and SQLE-were found to significantly impact the proliferation, migration, and apoptosis of osteosarcoma cells, highlighting their potential as key prognostic markers and therapeutic targets. OS-PCDS enables accurate evaluation of the prognosis in patients with osteosarcoma.

Challenges of Regulated Cell Death: Implications for Therapy Resistance in Cancer

Regulated cell death, a regulatory form of cell demise, has been extensively studied in multicellular organisms. It plays a pivotal role in maintaining organismal homeostasis under normal and pathological conditions. Although alterations in various regulated cell death modes are hallmark features of tumorigenesis, they can have divergent effects on cancer cells. Consequently, there is a growing interest in targeting these mechanisms using small-molecule compounds for therapeutic purposes, with substantial progress observed across various human cancers. This review focuses on summarizing key signaling pathways associated with apoptotic and autophagy-dependent cell death. Additionally, it explores crucial pathways related to other regulated cell death modes in the context of cancer. The discussion delves into the current understanding of these processes and their implications in cancer treatment, aiming to illuminate novel strategies to combat therapy resistance and enhance overall cancer therapy.

MIF inhibition attenuates intervertebral disc degeneration by reducing nucleus pulposus cell apoptosis and inflammation

Nucleus pulposus cells (NPCs) apoptosis and inflammation are the extremely critical factors of intervertebral disc degeneration (IVDD). Nevertheless, the underlying procedure remains mysterious. Macrophage migration inhibitory factor (MIF) is a cytokine that promotes inflammation and has been demonstrated to have a significant impact on apoptosis and inflammation. For this research, we employed a model of NPCs degeneration stimulated by lipopolysaccharides (LPS) and a rat acupuncture IVDD model to examine the role of MIF in vitro and in vivo, respectively. Initially, we verified that there was a significant rise of MIF expression in the NP tissues of individuals with IVDD, as well as in rat models of IVDD. Furthermore, this augmented expression of MIF was similarly evident in degenerated NPCs. Afterwards, it was discovered that ISO-1, a MIF inhibitor, effectively decreased the quantity of cells undergoing apoptosis and inhibited the release of inflammatory molecules (TNF-α, IL-1β, IL-6). Furthermore, it has been shown that the PI3K/Akt pathway plays a vital part in the regulation of NPCs degeneration by MIF. Ultimately, we showcased that the IVDD process was impacted by the MIF inhibitor in the rat model. In summary, our experimental results substantiate the significant involvement of MIF in the degeneration of NPCs, and inhibiting MIF activity can effectively mitigate IVDD.

Analyzing the involvement of diverse cell death-related genes in diffuse large B-cell lymphoma using bioinformatics techniques

Diffuse large B-cell lymphoma (DLBCL) stands as the most prevalent subtype of non-Hodgkin's lymphoma and exhibits significant heterogeneity. Various forms of programmed cell death (PCD) have been established to have close associations with tumor onset and progression. To this end, this study has compiled 16 PCD-related genes. The investigation delved into genes linked with prognosis, constructing risk models through consecutive application of univariate Cox regression analysis and Lasso-Cox regression analysis. Furthermore, we employed RT-qPCR to validate the mRNA expression levels of certain diagnosis-related genes. Subsequently, the models underwent validation through KM survival curves and ROC curves, respectively. Additionally, nomogram models were formulated employing prognosis-related genes and risk scores. Lastly, disparities in immune cell infiltration abundance and the expression of immune checkpoint-associated genes between high- and low-risk groups, as classified by risk models, were explored. These findings contribute to a more comprehensive understanding of the role played by the 16 PCD-associated genes in DLBCL, shedding light on potential novel therapeutic strategies for the condition.

Distinct cuproptosis patterns in hepatocellular carcinoma patients correlate with unique immune microenvironment characteristics and cell-cell communication, contributing to varied overall survival outcomes

Background

Hepatocellular carcinoma (HCC), a prevalent cancer, is linked to cuproptosis in tumor progression. However, cuproptosis's impact on HCC prognosis and its role in the tumor microenvironment remain unclear. We aimed to explore the correlation between cellular cuproptosis and the immune microenvironment in HCC, providing potential immunotherapeutic insights.

Methods

Examining cuproptosis-related genes and the immune microenvironment through consensus clustering and WGCNA. Risk models were constructed using LASSO Cox analysis and validated in an independent cohort. Gene expression data from The Cancer Genome Atlas (TCGA) database and single-cell RNA sequencing (scRNA-seq) data from the Gene Expression Omnibus (GEO) database were utilized. We scored cuproptosis expression and explored immunoinfiltration and cell-cell communication. Differential signals in T_memory cells were compared across different cuproptosis levels.

Results

Cuproptosis genes associated with fibroblast recruitment (GLS) and macrophage infiltration (FDX1). Liver cancer patients categorized into two subtypes based on cuproptosis gene expression. High expression of DLAT, GLS, and CDKN2A linked to immunosuppression (TGF-β), while high FDX1, MTF1, LIAS, and LIPT1 expression enhanced communication with non-immune cells. Developed reliable prognostic signature score and nomogram using cuproptosis-related genes. Single-cell analysis revealed differences in T_memory and TAM infiltration based on cuproptosis scores, with SPP1 and MIF as dominant signaling molecules. Finally, the results of in vitro experiments showed that when DLAT or CDKN2A was knocked down, the proliferation, migration, and invasion of HCC cells were significantly decreased.

Conclusion

Our study demonstrates that cuproptosis affects the immune microenvironment and cell-cell communication. Identified 9 genetic markers predicting survival outcomes and immunotherapy responses. Evaluating cuproptosis signaling can optimize immunotherapeutic strategies for hepatocellular carcinoma.

Elucidating the impact of parthanatos-related microRNAs on the tumoral immune microenvironment and clinical outcome in low-grade gliomas

Parthanatos, a cell death mechanism triggered by PARP-1 activation, is implicated in oncogenic processes, yet their role in low-grade gliomas (LGG) remains poorly understood. This research investigates Parthanatos-related miRNAs' prognostic and immunomodulatory potential, alongside their influence on therapeutic outcomes in LGGs. Comprehensive miRNA and mRNA profiles of LGG patients were extracted from TCGA and CGGA databases, integrating clinical parameters to identify Parthanatos-associated miRNAs. IHC data validated the expression levels of Parthanatos-related genes in glioma versus normal brain tissues. Protein-protein interaction networks and Spearman correlation analysis facilitated the identification of key miRNAs. Parthanatos-related miRNA indices (PMI) were screened using Lasso and assessed for their accuracy in predicting prognosis, comparing their associated potential molecular functions and heterogeneity of the immune microenvironment. Drug sensitivity was assessed between different groups and optimal therapeutic agents were predicted. Validate the expression levels of key miRNAs by qPCR. Ninety-one miRNAs significantly associated with Parthanatos were screened, through which a PMI prognosis model of nine miRNAs was constructed. The PMI score was able to independently predict the prognosis of patients with LGG, and the nomogram constructed based on the PMI provided a practical tool for clinical prediction of patient prognosis. The proportion of immune response was lower in patients in the high-risk group, and there were significant differences in drug sensitivity between different risk classes, while drugs such as Fasudil were identified as the most promising therapeutic agents for patients in the high-risk group. Our findings highlight the critical role of Parthanatos-associated miRNAs in the progression and treatment of LGG, offering novel insights into their prognostic value and therapeutic potential.

Mechanisms of chondrocyte regulated cell death in osteoarthritis: Focus on ROS-triggered ferroptosis, parthanatos, and oxeiptosis

Osteoarthritis (OA) is a common chronic inflammatory degenerative disease. Since chondrocytes are the only type of cells in cartilage, their survival is critical for maintaining cartilage morphology. This review offers a comprehensive analysis of how reactive oxygen species (ROS), including superoxide anions, hydrogen peroxide, hydroxyl radicals, nitric oxide, and their derivatives, affect cartilage homeostasis and trigger several novel modes of regulated cell death, including ferroptosis, parthanatos, and oxeiptosis, which may play roles in chondrocyte death and OA development. Moreover, we discuss potential therapeutic strategies to alleviate OA by scavenging ROS and provide new insight into the research and treatment of the role of regulated cell death in OA.

Identification of Poly(ADP-ribose) Polymerase 9 (PARP9) as a Potent Suppressor for Mycobacterium tuberculosis Infection

ADP-ribosylation is a reversible and dynamic post-translational modification mediated by ADP-ribosyltransferases (ARTs). Poly(ADP-ribose) polymerases (PARPs) are an important family of human ARTs. ADP-ribosylation and PARPs have crucial functions in host-pathogen interaction, especially in viral infections. However, the functions and potential molecular mechanisms of ADP-ribosylation and PARPs in Mycobacterium infection remain unknown. In this study, bioinformatics analysis revealed significantly changed expression levels of several PARPs in tuberculosis patients compared to healthy individuals. Moreover, the expression levels of these PARPs returned to normal following tuberculosis treatment. Then, the changes in the expression levels of PARPs during Mycobacterium infection were validated in Tohoku Hospital Pediatrics-1 (THP1)-induced differentiated macrophages infected with Mycobacterium model strains bacillus Calmette-Guérin (BCG) and in human lung adenocarcinoma A549 cells infected with Mycobacterium smegmatis (Ms), respectively. The mRNA levels of PARP9, PARP10, PARP12, and PARP14 were most significantly increased during infection, with corresponding increases in protein levels, indicating the possible biological functions of these PARPs during Mycobacterium infection. In addition, the biological function of host PARP9 in Mycobacterium infection was further studied. PARP9 deficiency significantly increased the infection efficiency and intracellular proliferation ability of Ms, which was reversed by the reconstruction of PARP9. Collectively, this study updates the understanding of changes in PARP expression during Mycobacterium infection and provides evidence supporting PARP9 as a potent suppressor for Mycobacterium infection.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43657-023-00112-2.

Integrated single-cell sequencing, spatial transcriptome sequencing and bulk RNA sequencing highlights the molecular characteristics of parthanatos in gastric cancer

BACKGROUND

Parthanatos is a novel programmatic form of cell death based on DNA damage and PARP-1 dependency. Nevertheless, its specific role in the context of gastric cancer (GC) remains uncertain.

METHODS

In this study, we integrated multi-omics algorithms to investigate the molecular characteristics of parthanatos in GC. A series of bioinformatics algorithms were utilized to explore clinical heterogeneity of GC and further predict the clinical outcomes.

RESULTS

Firstly, we conducted a comprehensive analysis of the omics features of parthanatos in various human tumors, including genomic mutations, transcriptome expression, and prognostic relevance. We successfully identified 7 cell types within the GC microenvironment: myeloid cell, epithelial cell, T cell, stromal cell, proliferative cell, B cell, and NK cell. When compared to adjacent non-tumor tissues, single-cell sequencing results from GC tissues revealed elevated scores for the parthanatos pathway across multiple cell types. Spatial transcriptomics, for the first time, unveiled the spatial distribution characteristics of parthanatos signaling. GC patients with different parthanatos signals often exhibited distinct immune microenvironment and metabolic reprogramming features, leading to different clinical outcomes. The integration of parthanatos signaling and clinical indicators enabled the creation of novel survival curves that accurately assess patients' survival times and statuses.

CONCLUSIONS

In this study, the molecular characteristics of parthanatos' unicellular and spatial transcriptomics in GC were revealed for the first time. Our model based on parthanatos signals can be used to distinguish individual heterogeneity and predict clinical outcomes in patients with GC.

Molecular prognostic of nine parthanatos death-related genes in glioma, particularly in COL8A1 identification

Post-operative progression and chemotherapy resistance are the main causes of treatment failure in glioma patients. There is a lack of ideal prediction models for post-operative glioma patient progression and drug sensitivity. We aimed to develop a prognostic model of parthanatos mRNA biomarkers for glioma outcomes. A total of 11 parthanatos genes were obtained from ParthanatosCluster database. ConsensusClusterPlus and R "Limma" package were used to cluster The Cancer Genome Atlas (TCGA)-glioma cohort and analyze the differential mRNAs. Univariate Cox regression analysis, random survival forest model, and least absolute shrinkage and selection operator (LASSO) regression analysis were used to determine the nine ParthanatosScore prognostic genes combination. ParthanatosScore was verified by 656 patients and 979 patients in TCGA and CGCA-LGG/GBM datasets. Differences in genomic mutations, tumor microenvironments, and functional pathways were assessed. Drug response prediction was performed using pRRophetic. Kaplan-Meier survival analysis was analyzed. Finally, COL8A1 was selected to evaluate its potential biological function and drug sensitivity of temozolomide and AZD3759 in glioma cells. ParthanatosScore obtained a combination of nine glioma prognostic genes, including CD58, H19, TNFAIP6, FTLP3, TNFRSF11B, SFRP2, LOXL1, COL8A1, and FABP5P7. In the TCGA-LGG/GBM dataset, glioma prognosis was poor in high ParthanatosScore. Low-score glioma patients were sensitive to AZD3759_1915, AZD5582_1617, AZD8186_1918, Dasatinib_1079, and Temozolomide_1375, while high-score patients were less sensitive to these drugs. Compared with HA cells, COL8A1 was significantly over-expressed in LN229 and U251 cells. Silencing COL8A1 inhibited the malignant characterization of LN229 and U251 cells. Temozolomide and AZD3759 also promoted parthanatos gene expression in glioma cells. Temozolomide and AZD3759 inhibited COL8A1 expression and cell viability and promoted apoptosis in glioma cells and PGM cells. ParthanatosScore can accurately predict clinical prognosis and drug sensitivity after glioma surgery. Silencing COL8A1 inhibited the malignant characterization. Temozolomide and AZD3759 inhibited COL8A1 expression and cell viability and promoted apoptosis and parthanatos gene expression, which is a target to improve glioma.

Assessing the Causal Relationship between Genetically Determined Inflammatory Cytokines and Parkinson's Disease Risk: A Bidirectional Two-Sample Mendelian Randomization Study

Background

Observational studies have suggested an association between inflammatory cytokines and Parkinson's disease (PD). This Mendelian randomization (MR) was conducted to further assess the causal correlations between inflammatory cytokines and PD.

Methods

Genetic instruments associated with inflammatory cytokines were extracted from a large summary genome-wide association studies (GWAS) involving 8,293 European participants. Summary-level statistics for PD were obtained from a large-sample GWAS containing 17 studies that involved European participants. Causalities of exposures and outcomes were explored mainly using inverse variance weighted (IVW) method.

Results

The IVW method indicated that basic fibroblast growth factor (FGFBasic), interleukin-2 (IL-2), and macrophage migration inhibitory factor (MIF) may be suggestively associated with the risk of PD (OR: 0.71, 95%CI: 0.52-0.96, P = 0.027; OR: 1.18, 95%CI: 1.01-1.38, P = 0.041; and OR: 1.23, 95%CI: 1.04-1.46, P = 0.018). In the reverse direction, monokine induced by interferon gamma (MIG), beta nerve growth factor (bNGF), interleukin-17 (IL-17), and interferon gamma (IFNg) are suggested to be the consequences of PD.

Conclusion

Our MR analysis indicated that suggestive associations between circulating levels of FGFBasic, IL-2, and MIF and PD risk. In addition, MIG, bNGF, IL-17, and IFNg are more likely to be involved in the development of downstream PD.

Resveratrol Preconditioning Downregulates PARP1 Protein to Alleviate PARP1-Mediated Cell Death Following Cerebral Ischemia

Stroke remains a leading cause of mortality; however, available therapeutics are limited. The study of ischemic tolerance, in paradigms such as resveratrol preconditioning (RPC), provides promise for the development of novel prophylactic therapies. The heavily oxidative environment following stroke promotes poly-ADP-ribose polymerase 1 (PARP1)-overactivation and parthanatos, both of which are major contributors to neuronal injury. In this study, we tested the hypothesis that RPC instills ischemic tolerance through decreasing PARP1 overexpression and parthanatos following in vitro and in vivo cerebral ischemia. To test this hypothesis, we utilized rat primary neuronal cultures (PNCs) and middle cerebral artery occlusion (MCAO) in the rat as in vitro and in vivo models, respectively. RPC was administered 2 days preceding ischemic insults. RPC protected PNCs against oxygen and glucose deprivation (OGD)-induced neuronal loss, as well as increases in total PARP1 protein, implying protection against PARP1-overactivation. Twelve hours following OGD, we observed reductions in NAD+/NADH as well as an increase in AIF nuclear translocation, but RPC ameliorated NAD+/NADH loss and blocked AIF nuclear translocation. MCAO in the rat induced AIF nuclear translocation in the ischemic penumbra after 24 h, which was ameliorated with RPC. We tested the hypothesis that RPC's neuroprotection was instilled through long-term downregulation of nuclear PARP1 protein. RPC downregulated nuclear PARP1 protein for at least 6 days in PNCs, likely contributing to RPC's ischemic tolerance. This study describes a novel mechanism by which RPC instills prophylaxis against ischemia-induced PARP1 overexpression and parthanatos, through a long-term reduction of nuclear PARP1 protein.

Regulated cell death in glioma: promising targets for natural small-molecule compounds

Gliomas are prevalent malignant tumors in adults, which can be categorized as either localized or diffuse gliomas. Glioblastoma is the most aggressive and deadliest form of glioma. Currently, there is no complete cure, and the median survival time is less than one year. The main mechanism of regulated cell death involves organisms coordinating the elimination of damaged cells at risk of tumor transformation or cells hijacked by microorganisms for pathogen replication. This process includes apoptosis, necroptosis, autophagy, ferroptosis, pyroptosis, necrosis, parthanayosis, entosis, lysosome-dependent death, NETosis, oxiptosis, alkaliptosis, and disulfidaptosis. The main goal of clinical oncology is to develop therapies that promote the effective elimination of cancer cells by regulating cell death are the main goal of clinical oncology. Recently, scientists have utilized pertinent regulatory factors and natural small-molecule compounds to induce regulated cell death for the treatment of gliomas. By analyzing the PubMed and Web of Science databases, this paper reviews the research progress on the regulation of cell death and the role of natural small-molecule compounds in glioma. The aim is to provide help for the treatment of glioblastoma.

Pyroptotic cell death: an emerging therapeutic opportunity for radiotherapy

Pyroptotic cell death, an inflammatory form of programmed cell death (PCD), is emerging as a potential therapeutic opportunity for radiotherapy (RT). RT is commonly used for cancer treatment, but its effectiveness can be limited by tumor resistance and adverse effects on healthy tissues. Pyroptosis, characterized by cell swelling, membrane rupture, and release of pro-inflammatory cytokines, has been shown to enhance the immune response against cancer cells. By inducing pyroptotic cell death in tumor cells, RT has the potential to enhance treatment outcomes by stimulating anti-tumor immune responses and improving the overall efficacy of RT. Furthermore, the release of danger signals from pyroptotic cells can promote the recruitment and activation of immune cells, leading to a systemic immune response that may target distant metastases. Although further research is needed to fully understand the mechanisms and optimize the use of pyroptotic cell death in RT, it holds promise as a novel therapeutic strategy for improving cancer treatment outcomes. This review aims to synthesize recent research on the regulatory mechanisms underlying radiation-induced pyroptosis and to elucidate the potential significance of this process in RT. The insights gained from this analysis may inform strategies to enhance the efficacy of RT for tumors.

A modified nucleoside O6-methyl-2'-deoxyguanosine-5'-triphosphate exhibits anti-glioblastoma activity in a caspase-independent manner

Resistance to temozolomide (TMZ), the frontline chemotherapeutic agent for glioblastoma (GBM), has emerged as a formidable obstacle, underscoring the imperative to identify alternative therapeutic strategies to improve patient outcomes. In this study, we comprehensively evaluated a novel agent, O6-methyl-2'-deoxyguanosine-5'-triphosphate (O6-methyl-dGTP) for its anti-GBM activity both in vitro and in vivo. Notably, O6-methyl-dGTP exhibited pronounced cytotoxicity against GBM cells, including those resistant to TMZ and overexpressing O6-methylguanine-DNA methyltransferase (MGMT). Mechanistic investigations revealed that O6-methyl-dGTP could be incorporated into genomic DNA, disrupting nucleotide pools balance, and inducing replication stress, resulting in S-phase arrest and DNA damage. The compound exerted its anti-tumor properties through the activation of AIF-mediated apoptosis and the parthanatos pathway. In vivo studies using U251 and Ln229 cell xenografts supported the robust tumor-inhibitory capacity of O6-methyl-dGTP. In an orthotopic transplantation model with U87MG cells, O6-methyl-dGTP showcased marginally superior tumor-suppressive activity compared to TMZ. In summary, our research, for the first time, underscores the potential of O6-methyl-dGTP as an effective candidate against GBM, laying a robust scientific groundwork for its potential clinical adoption in GBM treatment regimens.

Arnicolide D Inhibits Oxidative Stress-induced Breast Cancer Cell Growth and Invasion through Apoptosis, Ferroptosis, and Parthanatos

BACKGROUND

Breast cancer is the most common malignant tumor in women, and its pathogenesis is very complicated. More and more studies have found that Traditional Chinese Medicine plays an important role in tumor prevention.

OBJECTIVE

To investigate the mechanism of arnicolide D isolated from Centipeda minima in breast cancer.

METHODS

Cell Counting Kit-8 (CCK-8), western blot, RT-qPCR, ELISA, flow cytometry, and Transwell were used to detect the effect of arnicolide D on the biological function of breast cancer cells.

RESULTS

Arnicolide D promoted reactive oxygen species (ROS) production and induced a decrease in mitochondrial membrane potential in breast cancer cells, thereby inhibiting cell viability and increasing lactate dehydrogenase (LDH) release. Arnicolide D activated the classical apoptosis pathway to induce cell apoptosis; it significantly promoted PARP-1 expression, enhanced the nuclear translocation of apoptosis-inducing factor (AIF), and reduced the expression of AIF in mitochondria, indicating that it can induce the occurrence of parthanatos in a ROS dependent manner. In addition, arnicolide D down-regulated glutathione peroxidase 4 (GPX4) expression and increased the accumulation of Fe2+ and malondialdehyde (MDA), thereby activating ferroptosis. Apoptosis inhibitor, ferroptosis inhibitor, PARP inhibitor, PARP-1 siRNA, AIF siRNA and GPX4 overexpression vector significantly attenuated the inhibitory effect of arnicolide D on cell viability and reduced LDH release, which indicates that arnicolide D inhibits breast cancer cell growth by inducing apoptosis, parthanatos and ferroptosis. Arnicolide D also reduced breast cancer cell invasion and inhibited the expression of matrix metallopeptidase (MMP)-2 and MMP-9.

CONCLUSION

Arnicolide D can activate a variety of cell death modes by inducing oxidative stress, thereby inhibiting the growth and invasion of breast cancer cells, indicating that arnicolide D has a good anti-tumor effect.

Cell death classification: A new insight based on molecular mechanisms

Cells tend to disintegrate themselves or are forced to undergo such destructive processes in critical circumstances. This complex cellular function necessitates various mechanisms and molecular pathways in order to be executed. The very nature of cell death is essentially important and vital for maintaining homeostasis, thus any type of disturbing occurrence might lead to different sorts of diseases and dysfunctions. Cell death has various modalities and yet, every now and then, a new type of this elegant procedure gets to be discovered. The diversity of cell death compels the need for a universal organizing system in order to facilitate further studies, therapeutic strategies and the invention of new methods of research. Considering all that, we attempted to review most of the known cell death mechanisms and sort them all into one arranging system that operates under a simple but subtle decision-making (If \ Else) order as a sorting algorithm, in which it decides to place and sort an input data (a type of cell death) into its proper set, then a subset and finally a group of cell death. By proposing this algorithm, the authors hope it may solve the problems regarding newer and/or undiscovered types of cell death and facilitate research and therapeutic applications of cell death.

The cardiac glycoside ZINC253504760 induces parthanatos-type cell death and G2/M arrest via downregulation of MEK1/2 phosphorylation in leukemia cells

Overcoming multidrug resistance (MDR) represents a major obstacle in cancer chemotherapy. Cardiac glycosides (CGs) are efficient in the treatment of heart failure and recently emerged in a new role in the treatment of cancer. ZINC253504760, a synthetic cardenolide that is structurally similar to well-known GCs, digitoxin and digoxin, has not been investigated yet. This study aims to investigate the cytotoxicity of ZINC253504760 on MDR cell lines and its molecular mode of action for cancer treatment. Four drug-resistant cell lines (P-glycoprotein-, ABCB5-, and EGFR-overexpressing cells, and TP53-knockout cells) did not show cross-resistance to ZINC253504760 except BCRP-overexpressing cells. Transcriptomic profiling indicated that cell death and survival as well as cell cycle (G2/M damage) were the top cellular functions affected by ZINC253504760 in CCRF-CEM cells, while CDK1 was linked with the downregulation of MEK and ERK. With flow cytometry, ZINC253504760 induced G2/M phase arrest. Interestingly, ZINC253504760 induced a novel state-of-the-art mode of cell death (parthanatos) through PARP and PAR overexpression as shown by western blotting, apoptosis-inducing factor (AIF) translocation by immunofluorescence, DNA damage by comet assay, and mitochondrial membrane potential collapse by flow cytometry. These results were ROS-independent. Furthermore, ZINC253504760 is an ATP-competitive MEK inhibitor evidenced by its interaction with the MEK phosphorylation site as shown by molecular docking in silico and binding to recombinant MEK by microscale thermophoresis in vitro. To the best of our knowledge, this is the first time to describe a cardenolide that induces parthanatos in leukemia cells, which may help to improve efforts to overcome drug resistance in cancer. A cardiac glycoside compound ZINC253504760 displayed cytotoxicity against different multidrug-resistant cell lines. ZINC253504760 exhibited cytotoxicity in CCRF-CEM leukemia cells by predominantly inducing a new mode of cell death (parthanatos). ZINC253504760 downregulated MEK1/2 phosphorylation and further affected ERK activation, which induced G2/M phase arrest.

Non-apoptotic regulated cell death in Fuchs endothelial corneal dystrophy

Introduction

Fuchs endothelial corneal dystrophy (FECD) is the leading cause of corneal blindness in developed countries. Corneal endothelial cells in FECD are susceptive to oxidative stress, leading to mitochondrial dysfunction and cell death. Oxidative stress causes many forms of cell death including parthanatos, which is characterized by translocation of apoptosis-inducing factor (AIF) to the nucleus with upregulation of poly (ADP-ribose) polymerase 1 (PARP-1) and poly (ADP-ribose) (PAR). Although cell death is an important aspect of FECD, previous reports have often analyzed immortalized cell lines, making the evaluation of cell death difficult. Therefore, we established a new in vitro FECD model to evaluate the pathophysiology of FECD.

Methods

Corneal endothelial cells were derived from disease-specific induced pluripotent stem cells (iPSCs). Hydrogen peroxide (H2O2) was used as a source for oxidative stress to mimic the pathophysiology of FECD. We investigated the responses to oxidative stress and the involvement of parthanatos in FECD-corneal endothelial cells.

Results

Cell death ratio and oxidative stress level were upregulated in FECD with H2O2 treatment compared with non-FECD control, indicating the vulnerability of oxidative stress in FECD. We also found that intracellular PAR, as well as PARP-1 and AIF in the nucleus were upregulated in FECD. Furthermore, PARP inhibition, but not pan-caspase inhibition, rescued cell death, DNA double-strand breaks, mitochondrial membrane potential depolarization and energy depletion, suggesting that cell death was mainly due to parthanatos.

Conclusions

We report that parthanatos may be involved in the pathophysiology of FECD and targeting this cell death pathway may be a potential therapeutic approach for FECD.

Different types of cell death in diabetic endothelial dysfunction

Diabetes mellitus is a metabolic disease caused by disorders of insulin secretion and utilization. Long-term hyperglycemia, insulin resistance, and disorders of glucose and lipid metabolism cause vascular endothelial cell damage. Endothelial dysfunction is a key feature of diabetic vascular complications such as diabetic nephropathy, retinopathy, neuropathy, and atherosclerosis. Importantly, cell death is thought to be a key factor contributing to vascular endothelial injury. Morphologically, cell death can be divided into three forms: type I apoptosis, type II autophagy, and type III necrosis. According to the difference in function, cell death can be divided into accidental cell death (ACD) and regulated cell death (RCD). RCD is a controlled process involving numerous proteins and precise signaling cascades. Multiple subroutines covered by RCD may be involved in diabetic endothelial dysfunction, including apoptosis, autophagy, necroptosis, pyroptosis, entosis, ferroptosis, ferroautophagy, parthanatos, netotic cell death, lysosome-dependent cell death, alkaliptosis, oxeiptosis, cuproptosis, and PANoptosis. This article briefly reviews the mechanism and significance of cell death associated with diabetic endothelial dysfunction, which will help deepen the understanding of diabetic endothelial cell death and provide new therapeutic ideas.

A prognostic risk model for programmed cell death and revealing TRIB3 as a promising apoptosis suppressor in renal cell carcinoma

Programmed cell death (PCD), a common modality of cell death, affects tumor development and acts as a target for tumor therapeutics. Many modalities of PCD regulate genesis, progression and metastasis of cancers, thus affecting the patients' prognosis, but the comprehensive molecular mechanisms of PCD in tumors are lacking, especially in renal cancer. Here, seventeen PRPCDGs were identified from 1257 genes associated with thirteen PCD modalities, which were highly differentially expressed and significantly affected patients' prognosis. Then, LASSO regression analysis of these PRPCDGs screened the 9-gene PRPCDGs risk signature in TCGA-KIRC database. The PRPCDGs risk signature was closely associated with the patients' prognosis and presented stable prediction efficacy for 5- and 7-year overall survival (OS) in three different cohorts of renal cancer. Immune cell infiltration, immune checkpoint expression and pathway enrichment (including GO, KEGG pathway, tumor-associated pathways and metabolism-associated pathways) were significantly different in the high- or low-PRPCDGs-risk group. Finally, we illustrated that TRIB3 might be a protumor factor responsible for the elevated proliferation and invasion capacities of renal cell carcinoma (RCC) cells. In summary, the PRPCDGs risk signature was developed and showed stable prediction efficacy for the prognosis of patients and that (such as TRIB3) could be a potential target for RCC management.

Leveraging diverse cell-death patterns to predict the prognosis, immunotherapy and drug sensitivity of clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) poses clinical challenges due to its varied prognosis, tumor microenvironment attributes, and responses to immunotherapy. We established a novel Programmed Cell Death-related Signature (PRS) for ccRCC assessment, derived through the Least Absolute Shrinkage and Selection Operator (LASSO) regression method. We validated PRS using the E-MTAB-1980 dataset and created PCD-related clusters via non-negative matrix factorization (NMF). Our investigation included an in-depth analysis of immune infiltration scores using various algorithms. Additionally, we integrated data from the Cancer Immunome Atlas (TCIA) for ccRCC immunotherapy insights and leveraged the Genomics of Drug Sensitivity in Cancer (GDSC) database to assess drug sensitivity models. We complemented our findings with single-cell sequencing data and employed the Clinical Proteomic Tumor Analysis Consortium (CPTAC) and qRT-PCR to compare gene expression profiles between cancerous and paracancerous tissues. PRS serves as a valuable tool for prognostication, immune characterization, tumor mutation burden estimation, immunotherapy response prediction, and drug sensitivity assessment in ccRCC. We identify five genes with significant roles in cancer promotion and three genes with cancer-suppressive properties, further validated by qRT-PCR and CPTAC analyses, showcasing gene expression differences in ccRCC tissues. Our study introduces an innovative PCD model that amalgamates diverse cell death patterns to provide accurate predictions for clinical outcomes, mutational profiles, and immune characteristics in ccRCC. Our findings hold promise for advancing personalized treatment strategies in ccRCC patients.

The Expression of Parthanatos Markers and miR-7 Mimic Protects Photoreceptors from Parthanatos by Repressing α-Synuclein in Retinal Detachment

Retinal detachment (RD) refers to the separation between the neuroepithelium and the pigment epithelium layer. It is an important disease leading to irreversible vision damage worldwide, in which photoreceptor cell death plays a major role. α-Synuclein (α-syn) is reportedly involved in numerous mechanisms of neurodegenerative diseases, but the association with photoreceptor damage in RD has not been studied. In this study, elevated transcription levels of α-syn and parthanatos proteins were observed in the vitreous of patients with RD. The expression of α-syn- and parthanatos-related proteins was increased in experimental rat RD, and was involved in the mechanism of photoreceptor damage, which was related to the decreased expression of miR-7a-5p (miR-7). Interestingly, subretinal injection of miR-7 mimic in rats with RD inhibited the expression of retinal α-syn and down-regulated the parthanatos pathway, thereby protecting retinal structure and function. In addition, interference with α-syn in 661W cells decreased the expression of parthanatos death pathway in oxygen and glucose deprivation model. In conclusion, this study demonstrates the presence of parthanatos-related proteins in patients with RD and the role of the miR-7/α-syn/parthanatos pathway in photoreceptor damage in RD.

Two palladium (II) complexes derived from halogen-substituted Schiff bases and 2-picolylamine induce parthanatos-type cell death in sensitive and multi-drug resistant CCRF-CEM leukemia cells

The use of cisplatin and its derivatives in cancer treatment triggered the interest in metal-containing complexes as potential novel anticancer agents. Palladium (II)-based complexes have been synthesized in recent years with promising antitumor activity. Previously, we described the synthesis and cytotoxicity of palladium (II) complexes containing halogen-substituted Schiff bases and 2-picolylamine. Here, we selected two palladium (II) complexes with double chlorine-substitution or double iodine-substitution that displayed the best cytotoxicity in drug-sensitive CCRF-CEM and multidrug-resistant CEM/ADR5000 leukemia cells for further biological investigation. Surprisingly, these compounds did not significantly induce apoptotic cell death. This study aims to reveal the major mode of cell death of these two palladium (II) complexes. We performed annexin V-FITC/PI staining and flow cytometric mitochondrial membrane potential measurement followed by western blotting, immunofluorescence microscopy, and alkaline single cell electrophoresis (comet assay). J4 and J6 still induced neither apoptosis nor necrosis in both leukemia cell lines. They also insufficiently induced autophagy as evidenced by Beclin and p62 detection in western blotting. Interestingly, J4 and J6 induced a novel mode of cell death (parthanatos) as mainly demonstrated in CCRF-CEM cells by hyper-activation of poly(ADP-ribose) polymerase 1 (PARP) and poly(ADP-ribose) (PAR) using western blotting, flow cytometric measurement of mitochondrial membrane potential collapse, nuclear translocation of apoptosis-inducing factor (AIF) by immunofluorescence microscopy, and DNA damage by alkaline single cell electrophoresis (comet assay). AIF translocation was also observed in CEM/ADR5000 cells. Thus, parthanatos was the predominant mode of cell death induced by J4 and J6, which explains the high cytotoxicity in CCRF-CEM and CEM/ADR5000 cells. J4 and J6 may be interesting drug candidates and deserve further investigations to overcome resistance of tumors against apoptosis. This study will promote the design of further novel palladium (II)-based complexes as chemotherapeutic agents.

FOXA2 attenuates lipopolysaccharide‑induced pneumonia by inhibiting the inflammatory response, oxidative stress and apoptosis through blocking of p38/STAT3 signaling

Pneumonia is a severe inflammatory disease of the lung. Forkhead box protein A2 (FOXA2) has been demonstrated to serve an important regulatory role in various pulmonary diseases; however, the role of FOXA2 in pneumonia remains to be elucidated. The present study aimed to explore the functional effects and regulatory mechanism of FOXA2 in pneumonia. An in vitro pneumonia model was induced using lipopolysaccharide (LPS) in WI-38 cells. The mRNA and protein expression levels of FOXA2 were determined by reverse transcription-quantitative PCR and western blotting, respectively. Cell viability was assessed using a Cell Counting Kit-8 assay. Inflammatory cytokines were evaluated using ELISA kits and oxidative stress markers were assessed using a malondialdehyde assay kit, superoxide dismutase assay kit and CATalase assay kit. Cell apoptosis was evaluated using flow cytometry and the caspase3 activity was determined. Western blotting was performed to examine the protein expression levels of endoplasmic reticulum stress (ERS)-associated factors. For a rescue assay, a p38 MAPK activator, U46619, was used to investigate the regulatory mechanism of FOXA2 involving p38/STAT3 signaling. FOXA2 was downregulated in LPS-induced WI-38 cells. FOXA2 overexpression alleviated LPS-induced inflammation, oxidative stress, apoptosis and ERS in WI-38 cells. Furthermore, the inhibitory effects of FOXA2 on inflammation, oxidative stress and apoptosis, as well as ERS in LPS-induced WI-38 cells were partly weakened by additional treatment with U46619. In conclusion, FOXA2 served a protective role against LPS-induced pneumonia by regulating p38/STAT3 signaling, providing a novel idea for the development of targeted therapeutic strategies for pneumonia.

The old second messenger cAMP teams up with novel cell death mechanisms: potential translational therapeutical benefit for Alzheimer's disease and Parkinson's disease

Alzheimer's disease (AD) and Parkinson's disease (PD) represent the most prevalent neurodegenerative disorders severely impacting life expectancy and quality of life of millions of people worldwide. AD and PD exhibit both a very distinct pathophysiological disease pattern. Intriguingly, recent researches, however, implicate that overlapping mechanisms may underlie AD and PD. In AD and PD, novel cell death mechanisms, encompassing parthanatos, netosis, lysosome-dependent cell death, senescence and ferroptosis, apparently rely on the production of reactive oxygen species, and seem to be modulated by the well-known, "old" second messenger cAMP. Signaling of cAMP via PKA and Epac promotes parthanatos and induces lysosomal cell death, while signaling of cAMP via PKA inhibits netosis and cellular senescence. Additionally, PKA protects against ferroptosis, whereas Epac1 promotes ferroptosis. Here we review the most recent insights into the overlapping mechanisms between AD and PD, with a special focus on cAMP signaling and the pharmacology of cAMP signaling pathways.

Advances in tumor nanotechnology: theragnostic implications in tumors via targeting regulated cell death

Cell death constitutes an indispensable part of the organismal balance in the human body. Generally, cell death includes regulated cell death (RCD) and accidental cell death (ACD), reflecting the intricately molecule-dependent process and the uncontrolled response, respectively. Furthermore, diverse RCD pathways correlate with multiple diseases, such as tumors and neurodegenerative diseases. Meanwhile, with the development of precision medicine, novel nano-based materials have gradually been applied in the clinical diagnosis and treatment of tumor patients. As the carrier, organic, inorganic, and biomimetic nanomaterials could facilitate the distribution, improve solubility and bioavailability, enhance biocompatibility and decrease the toxicity of drugs in the body, therefore, benefiting tumor patients with better survival outcomes and quality of life. In terms of the most studied cell death pathways, such as apoptosis, necroptosis, and pyroptosis, plenty of studies have explored specific types of nanomaterials targeting the molecules and signals in these pathways. However, no attempt was made to display diverse nanomaterials targeting different RCD pathways comprehensively. In this review, we elaborate on the potential mechanisms of RCD, including intrinsic and extrinsic apoptosis, necroptosis, ferroptosis, pyroptosis, autophagy-dependent cell death, and other cell death pathways together with corresponding nanomaterials. The thorough presentation of RCD pathways and diverse nano-based materials may provide a wider cellular and molecular landscape of tumor diagnosis and treatments.

Natural and synthetic compounds for glioma treatment based on ROS-mediated strategy

Glioma is the most frequent and most malignant tumor of the central nervous system (CNS)，accounting for about 50% of all CNS tumor and approximately 80% of the malignant primary tumors in the CNS. Patients with glioma benefit from surgical resection, chemo- and radio-therapy. However these therapeutical strategies do not significantly improve the prognosis, nor increase survival rates owing to restricted drug contribution in the CNS and to the malignant characteristics of glioma. Reactive oxygen species (ROS) are important oxygen-containing molecules that regulate tumorigenesis and tumor progression. When ROS accumulates to cytotoxic levels, this can lead to anti-tumor effects. Multiple chemicals used as therapeutic strategies are based on this mechanism. They regulate intracellular ROS levels directly or indirectly, resulting in the inability of glioma cells to adapt to the damage induced by these substances. In the current review, we summarize the natural products, synthetic compounds and interdisciplinary techniques used for the treatment of glioma. Their possible molecular mechanisms are also presented. Some of them are also used as sensitizers: they modulate ROS levels to improve the outcomes of chemo- and radio-therapy. In addition, we summarize some new targets upstream or downstream of ROS to provide ideas for developing new anti-glioma therapies.

Fighting secondary triple-negative breast cancer in cerebellum: A powerful aid from a medicinal mushrooms blend

Breast cancer (BC) is the second most common cause of brain metastasis onset in patients, with the cerebellum accounting for the 33% of cases. In the current study, using a 4T1 triple-negative mouse BC model, we revealed that an orally administered medicinal mushrooms (MM) blend, rich in β-glucans, played a direct and specific anti-cancer action on cerebellar metastases, also bettering locomotor performances. The neuroprotective effect of the MM blend plays through (i) a direct and specific inhibition of cerebellar metastatization pattern typical of TNBC (with an induced reduction of about 50% of metastases density) and (ii) the regulation of apoptosis and proliferation-related genes, as suggested by expression changes of specific molecular markers, i.e. PCNA, p53, Bcl2, BAX, CASP9, CASP3, Hsp70 and AIF. Therefore, inhibiting the metastatization process, triggering a significant apoptosis increase, and lessening cell proliferation, this MM supplement, employed as adjuvant treatment in association with conventional therapy, could represent a promising approach, in the field of Integrative Oncology, for patients' management in both prevention and treatment of brain metastases from BC.

The natural product dehydrocurvularin induces apoptosis of gastric cancer cells by activating PARP-1 and caspase-3

The natural product dehydrocurvularin (DSE2) is a fungal-derived macrolide with potent anticancer activity, but the mechanism is still unclear. We found that DSE2 effectively inhibited the growth of gastric cancer cells and induced the apoptosis by activating Poly(ADP-ribose) polymerase 1 (PARP-1) and caspase-3. Pharmacological inhibition and genetic knockdown with PARP-1 or caspase-3 suppressed DSE2-induced apoptosis. PARP-1 was previously reported to be cleaved into fragments during apoptosis. However, PARP-1 was barely cleaved in DSE2-induced apoptosis. DSE2 induced PARP-1 activation as indicated by rapid depletion of NAD⁺ and the concomitant formation of poly(ADP-ribosylated) proteins (PARs). Interestingly, the PARP-1 inhibitor (Olaparib) attenuated the cytotoxicity of DSE2. Moreover, the combination of Olaparib and Z-DEVD-FMK (caspase-3 inhibitor) further reduced the cytotoxicity. It has been shown that PARP-1 activation triggers cytoplasm-nucleus translocation of apoptosis-inducing factor (AIF). Caspase-3 inhibitors inhibited PARP-1 activation and suppressed PARP-1-induced AIF nuclear translocation. These results indicated that DSE2-induced caspase-3 activation may occur before PARP-1 activation. The ROS inhibitor, N-acetyl-cysteine, significantly inhibited the activation of caspase-3 and PARP-1, indicating that ROS overproduction contributed to DSE2-induced apoptosis. Using an in vivo approach, we further found that DSE2 significantly inhibited gastric tumor growth and promoted translocation of AIF to the nucleus. In conclusion, DSE2 induces gastric cell apoptosis by activating caspase-3 and PARP-1, and shows potent antitumor activity against human gastric carcinoma in vitro and in vivo.

The ADP-ribose hydrolase NUDT5 is important for DNA repair

DNA damage leads to rapid synthesis of poly(ADP-ribose) (pADPr), which is important for damage signaling and repair. pADPr chains are removed by poly(ADP-ribose) glycohydrolase (PARG), releasing free mono(ADP-ribose) (mADPr). Here, we show that the NUDIX hydrolase NUDT5, which can hydrolyze mADPr to ribose-5-phosphate and either AMP or ATP, is recruited to damage sites through interaction with PARG. NUDT5 does not regulate PARP or PARG activity. Instead, loss of NUDT5 reduces basal cellular ATP levels and exacerbates the decrease in cellular ATP that occurs during DNA repair. Further, loss of NUDT5 activity impairs RAD51 recruitment, attenuates the phosphorylation of key DNA-repair proteins, and reduces both H2A.Z exchange at damage sites and repair by homologous recombination. The ability of NUDT5 to hydrolyze mADPr, and/or regulate cellular ATP, may therefore be important for efficient DNA repair. Targeting NUDT5 to disrupt PAR/mADPr and energy metabolism may be an effective anti-cancer strategy.

Nicaraven induces programmed cell death by distinct mechanisms according to the expression levels of Bcl-2 and poly (ADP-ribose) glycohydrolase in cancer cells

The PARP-1 expression level and poly (ADP-ribosyl)ation activity in cancer markedly affect the therapeutic outcome. Nicaraven, a free radical scavenger has been found to inhibit PARP, but the effect on cancer cells is still unclear. In this study, we investigated the potential role and molecular mechanism of nicaraven on cancer cells. Using U937 lymphoma cells and HCT-8 colorectal cancer cells, we found that nicaraven moderately reduced the cell viability of both cells in a dose-dependent manner. Interestingly, nicaraven significantly induced apoptosis of U937 cells that are dominantly expressing Bcl-2 but induced PAR-dependent cell death (parthanatos) of HCT-8 cells that are highly expressing poly (ADP-ribose) glycohydrolase (PARG). Based on our data, nicaraven seems to induce programmed cell death through distinct mechanisms, according to the expression levels of Bcl-2 and PARG in cancer cells.

Mixed in chains: NEDD8 polymers in the Protein Quality Control system

Post-translational modification of proteins with the Ubiquitin-like molecule NEDD8 is a critical regulatory mechanism for several biological processes and a potential target for therapeutic intervention. The role of NEDD8 has been mainly characterised through its modification as single moiety on the cullin family of proteins and control of Cullin-Ring-Ligases, but also on non-cullin substrates. In addition to monoNEDDylation, recent studies have now revealed that NEDD8 can also generate diverse polymers. This is either through modification of the 9 available lysines in NEDD8 and the formation of polyNEDD8 chains, or NEDDylation of Ubiquitin and SUMO-2 for the generation of hybrid NEDD8 chains. Here, we review recent findings that characterise the formation of NEDD8 polymers under distinct modes of protein NEDDylation (canonical/atypical) and their potential role as regulatory signals of the proteotoxic stress response and the Protein Quality Control system.

ROS-triggered endothelial cell death mechanisms: Focus on pyroptosis, parthanatos, and ferroptosis

The endothelium is a single layer of epithelium covering the surface of the vascular system, and it represents a physical barrier between the blood and vessel wall that plays an important role in maintaining intravascular homeostasis. However, endothelial dysfunction or endothelial cell death can cause vascular barrier disruption, vasoconstriction and diastolic dysfunction, vascular smooth muscle cell proliferation and migration, inflammatory responses, and thrombosis, which are closely associated with the progression of several diseases, such as atherosclerosis, hypertension, coronary atherosclerotic heart disease, ischemic stroke, acute lung injury, acute kidney injury, diabetic retinopathy, and Alzheimer's disease. Oxidative stress caused by the overproduction of reactive oxygen species (ROS) is an important mechanism underlying endothelial cell death. Growing evidence suggests that ROS can trigger endothelial cell death in various ways, including pyroptosis, parthanatos, and ferroptosis. Therefore, this review will systematically illustrate the source of ROS in endothelial cells (ECs); reveal the molecular mechanism by which ROS trigger pyroptosis, parthanatos, and ferroptosis in ECs; and provide new ideas for the research and treatment of endothelial dysfunction-related diseases.

Radiation-induced Cell Death and Its Mechanisms

ABSTRACT

With rapid technical advances, ionizing radiation has been put into wider application in ordinary living, with the worst cytological effect on the human body being cell death. Moreover, according to the Nomenclature Committee on Cell Death, the method of radiation-induced cell death, usually classified as interphase and proliferative death, undergoes more detailed classifications oriented by its molecular mechanism. Elaborating its mode and molecular mechanism is crucial for the protection and treatment of radiation injury, as well as the radiotherapy and recovery of tumors. Varying with the changes of the radiation dose and the environment, the diverse targets and pathways of ionizing radiation result in various cell deaths. This review focuses on classifications of radiation-induced cell death and its molecular mechanism. We also examine the main characteristics of ionizing radiation-induced cell death. The modes of radiation-induced cell death can be classified as apoptosis, necrosis, autophagy-dependent cell death, pyroptosis, ferroptosis, immunogenic cell death, and non-lethal processes. Once the dose is high enough, radiation effects mostly appear as destructiveness ("destructiveness" is used to describe a situation in which cells do not have the opportunity to undergo a routine death process, in which case high-dose radiation works like a physical attack). This breaks up or even shatters cells, making it difficult to find responses of the cell itself. Due to diversities concerning cell phenotypes, phases of cell cycle, radiation dose, and even cellular subregions, various methods of cell death occur, which are difficult to identify and classify. Additionally, the existence of common initial activation and signaling molecules among all kinds of cell deaths, as well as sophisticated crossways in cellular molecules, makes it more laborious to distinguish and classify various cell deaths.

Optimization of smashing tissue and ultrasonic extraction of tanshinones and their neuroprotective effect on cerebral ischemia/reperfusion injury by inhibiting parthanatos

A green smashing tissue and ultrasonic (STU) extraction method, which combines smashing tissue and ultrasonic-assisted extraction, was developed for the first time. The extraction of tanshinones from Salvia miltiorrhiza Bunge (SM) was taken as an example to discuss the practicability of this method. Taking the total yield of eight tanshinones as an evaluation index, response surface methodology (RSM) and artificial neural network (ANN) models were used to optimize the extraction parameters, and these two models were also compared by investigating the extract yield of tanshinones and the antioxidant activity of the obtained SM extract. The optimal STU conditions by ANN were as follows: an ethanol concentration of 73%, a liquid/solid ratio of 30 mL g^-1, a smashing tissue time of 97 s and an ultrasonic time of 40 min. Under these optimal conditions, the yield of the eight components was 0.30% ± 0.12, which was greater than 0.28% ± 0.03 optimized by RSM. The IC₅₀ values of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) of the obtained extract were 55.25 ± 3.72 μg mL^-1 and 67.33 ± 2.62 μg mL^-1, respectively, which were better than those of 75.49 ± 4.33 μg mL^-1 and 112.10 ± 5.98 μg mL^-1, respectively, optimized by RSM. Furthermore, the SM extract was found to exert neuroprotective effects by inhibiting parthanatos in middle cerebral artery occlusion/reperfusion (MCAO/R)-induced rats. The results supported the use of the SM extract, which was obtained by STU, as a potential product in the cosmetics, medicine, and food industries.

LCS-1 inhibition of superoxide dismutase 1 induces ROS-dependent death of glioma cells and degradates PARP and BRCA1

Gliomas are characterized by high morbidity and mortality, and have only slightly increased survival with recent considerable improvements for treatment. An innovative therapeutic strategy had been developed via inducing ROS-dependent cell death by targeting antioxidant proteins. In this study, we found that glioma tissues expressed high levels of superoxide dismutase 1 (SOD1). The expression of SOD1 was upregulated in glioma grade III and V tissues compared with that in normal brain tissues or glioma grade I tissues. U251 and U87 glioma cells expressed high levels of SOD1, low levels of SOD2 and very low levels of SOD3. LCS-1, an inhibitor of SOD1, increased the expression SOD1 at both mRNA and protein levels slightly but significantly. As expected, LCS-1 caused ROS production in a dose- and time-dependent manner. SOD1 inhibition also induced the gene expression of HO-1, GCLC, GCLM and NQO1 which are targeting genes of nuclear factor erythroid 2-related factor 2, suggesting the activation of ROS signal pathway. Importantly, LCS-1 induced death of U251 and U87 cells dose- and time-dependently. The cell death was reversed by the pretreatment of cells with ROS scavenges NAC or GSH. Furthermore, LCS-1 decreased the growth of xenograft tumors formed by U87 glioma cells in nude mice. Mechanistically, the inhibition of P53, caspases did not reverse LCS-1-induced cell death, indicating the failure of these molecules involving in cell death. Moreover, we found that LCS-1 treatment induced the degradation of both PARP and BRCA1 simultaneously, suggesting that LCS-1-induced cell death may be associated with the failure of DNA damage repair. Taking together, these results suggest that the degradation of both PARP and BRCA1 may contribute to cell death induced by SOD1 inhibition, and SOD1 may be a target for glioma therapy.

Molecular Mechanisms of Parthanatos and Its Role in Diverse Diseases

Differential evolution of apoptosis, programmed necrosis, and autophagy, parthanatos is a form of cell death mediated by poly(ADP-ribose) polymerase 1 (PARP1), which is caused by DNA damage. PARP1 hyper-activation stimulates apoptosis-inducing factor (AIF) nucleus translocation, and accelerates nicotinamide adenine dinucleotide (NAD⁺) and adenosine triphosphate (ATP) depletion, leading to DNA fragmentation. The mechanisms of parthanatos mainly include DNA damage, PARP1 hyper-activation, PAR accumulation, NAD⁺ and ATP depletion, and AIF nucleus translocation. Now, it is reported that parthanatos widely exists in different diseases (tumors, retinal diseases, neurological diseases, diabetes, renal diseases, cardiovascular diseases, ischemia-reperfusion injury...). Excessive or defective parthanatos contributes to pathological cell damage; therefore, parthanatos is critical in the therapy and prevention of many diseases. In this work, the hallmarks and molecular mechanisms of parthanatos and its related disorders are summarized. The questions raised by the recent findings are also presented. Further understanding of parthanatos will provide a new treatment option for associated conditions.

PAAN/MIF nuclease inhibition prevents neurodegeneration in Parkinson's disease

Parthanatos-associated apoptosis-inducing factor (AIF) nuclease (PAAN), also known as macrophage migration inhibitor factor (MIF), is a member of the PD-D/E(X)K nucleases that acts as a final executioner in parthanatos. PAAN's role in Parkinson's disease (PD) and whether it is amenable to chemical inhibition is not known. Here, we show that neurodegeneration induced by pathologic α-synuclein (α-syn) occurs via PAAN/MIF nuclease activity. Genetic depletion of PAAN/MIF and a mutant lacking nuclease activity prevent the loss of dopaminergic neurons and behavioral deficits in the α-syn preformed fibril (PFF) mouse model of sporadic PD. Compound screening led to the identification of PAANIB-1, a brain-penetrant PAAN/MIF nuclease inhibitor that prevents neurodegeneration induced by α-syn PFF, AAV-α-syn overexpression, or MPTP intoxication in vivo. Our findings could have broad relevance in human pathologies where parthanatos plays a role in the development of cell death inhibitors targeting the druggable PAAN/MIF nuclease.

Which cell death modality wins the contest for photodynamic therapy of cancer?

Photodynamic therapy (PDT) was discovered more than 100 years ago. Since then, many protocols and agents for PDT have been proposed for the treatment of several types of cancer. Traditionally, cell death induced by PDT was categorized into three types: apoptosis, cell death associated with autophagy, and necrosis. However, with the discovery of several other regulated cell death modalities in recent years, it has become clear that this is a rather simple understanding of the mechanisms of action of PDT. New observations revealed that cancer cells exposed to PDT can pass through various non-conventional cell death pathways, such as paraptosis, parthanatos, mitotic catastrophe, pyroptosis, necroptosis, and ferroptosis. Nowadays, immunogenic cell death (ICD) has become one of the most promising ways to eradicate tumor cells by activation of the T-cell adaptive immune response and induction of long-term immunological memory. ICD can be triggered by many anti-cancer treatment methods, including PDT. In this review, we critically discuss recent findings on the non-conventional cell death mechanisms triggered by PDT. Next, we emphasize the role and contribution of ICD in these PDT-induced non-conventional cell death modalities. Finally, we discuss the obstacles and propose several areas of research that will help to overcome these challenges and lead to the development of highly effective anti-cancer therapy based on PDT.