Sublethal necroptosis signaling promotes inflammation and liver cancer

Desulfovibrio vulgaris flagellin exacerbates colorectal cancer through activating LRRC19/TRAF6/TAK1 pathway

The initiation and progression of colorectal cancer (CRC) are intimately associated with genetic, environmental and biological factors. Desulfovibrio vulgaris (DSV), a sulfate-reducing bacterium, has been found excessive growth in CRC patients, suggesting a potential role in carcinogenesis. However, the precise mechanisms underlying this association remain incompletely understood. We have found Desulfovibrio was abundant in high-fat diet-induced Apcmin/+ mice, and DSV, a member of Desulfovibrio, triggered colonocyte proliferation of germ-free mice. Furthermore, the level of DSV progressively rose from healthy individuals to CRC patients. Flagella are important accessory structures of bacteria, which can help them colonize and enhance their invasive ability. We found that D. vulgaris flagellin (DVF) drove the proliferation, migration, and invasion of CRC cells and fostered the growth of CRC xenografts. DVF enriched the epithelial-mesenchymal transition (EMT)-associated genes and characterized the facilitation of DVF on EMT. Mechanistically, DVF induced EMT through a functional transmembrane receptor called leucine-rich repeat containing 19 (LRRC19). DVF interacted with LRRC19 to modulate the ubiquitination of tumor necrosis factor receptor-associated factor (TRAF)6, rather than TRAF2. This interaction drove the ubiquitination of pivotal molecule TAK1, further enhancing its autophosphorylation and ultimately contributing to EMT. Collectively, DVF interacts with LRRC19 to activate the TRAF6/TAK1 signaling pathway, thereby promoting the EMT of CRC. These data shed new light on the role of gut microbiota in CRC and establish a potential clinical therapeutic target.

RIPK3 in necroptosis and cancer

Receptor-interacting protein kinase-3 is essential for the cell death pathway called necroptosis. Necroptosis is activated by the death receptor ligands and pattern recognition receptors of the innate immune system, leading to significant consequences in inflammation and in diseases, particularly cancer. Necroptosis is highly proinflammatory compared with other modes of cell death because cell membrane integrity is lost, resulting in releases of cytokines and damage-associated molecular patterns that potentiate inflammation and activate the immune system. We discuss various ways that necroptosis is triggered along with its potential role in cancer and therapy.

Cell death, IL-1 cytokines, and tumor progression

Tumor cell death shapes tumorigenesis and antitumor immunity in complex ways. Recently, Hänggi et al. revealed that necrotic-like death releases interleukin-1α (IL-1α), driving myeloid-mediated immunosuppression. Lamorte et al. demonstrated that medullary sinus macrophage (MSM) efferocytosis of apoptotic tumor cells activates the IL-33-regulatory T cell (Treg) axis, accelerating tumor growth. Blocking these pathways enhances the efficacy of cancer immunotherapy.

Targeting B4GALT3 in BMSCs-EVs for Therapeutic Control of HCC via NF-κB pathway inhibition

Examining the communications in the tumor microenvironment (TME) specific to hepatocellular carcinoma (HCC), this exploration looks into the role played by beta-1,4-Galactosyltransferase III (B4GALT3) in bone marrow mesenchymal stromal cell-derived extracellular vesicles (BMSCs-EVs) regarding the NF-κB pathway and the triggering of cancer-associated fibroblasts (CAF). Through a multidisciplinary approach combining transcriptome sequencing, bioinformatic analysis, and various experimental models, the involvement of B4GALT3 in regulating CAF activity by modulating NF-κB signaling was brought to light in our study. The outcomes suggest that targeting B4GALT3 could impede HCC cell migration and invasion, promote apoptosis, and dampen tumor progression and metastasis, offering novel insights into potential therapeutic strategies for combating HCC.

An Anti-CD147 Antibody-Drug Conjugate Mehozumab-DM1 is Efficacious Against Hepatocellular Carcinoma in Cynomolgus Monkey

Effective treatment strategies are urgently needed for hepatocellular carcinoma (HCC) patients due to frequent therapeutic resistance and recurrence. Antibody-drug conjugate (ADC) is a specific antibody-drug conjugated with small molecular compounds, which has potent killing activity against cancer cells. However, few ADC candidates for HCC are undergoing clinical evaluation. CD147 is a tumor-associated antigen that is highly expressed on the surface of tumor cells. Here CD147 is found significantly upregulated in tumor tissues of HCC. Mehozumab-DM1, a humanized anti-CD147 monoclonal antibody conjugated with Mertansine (DM1) is developed. Mehozumab-DM1 is effectively internalized by cancer cells and demonstrated potent antitumor efficacy in HCC cells. In vivo evaluation of Mehozumab-DM1 is conducted in a CRISPR-mediated PTEN and TP53 mutation cynomolgus monkey liver cancer model, which is poorly responsive to sorafenib treatment. Mehozumab-DM1 demonstrated potent tumor inhibitory efficacy at doses of 0.2 and 1.0 mg kg-1 treatment groups in cynomolgus monkey. No treatment-related adverse reactions or body weight loss are observed. Interestingly, Mehozumab-DM1 treatment induced RIPK-dependent tumor cell necroptosis through inhibiting IκB kinase/NF-κB pathway. In conclusion, Mehozumab-DM1 potently inhibits hepatoma through effective internalization to release payload and inducing cell necroptosis to enhance the bystander effect, which is a promising treatment for refractory HCC.

Dying to survive: harnessing inflammatory cell death for better immunotherapy

Immunotherapy has transformed cancer treatment paradigms, but its effectiveness depends largely on the immunogenicity of the tumor. Unfortunately, the high resemblance of cancer to normal tissues makes most tumors immunologically 'cold', with a poor response to immunotherapy. Danger signals are critical for breaking immune tolerance and mobilizing robust, long-lasting antitumor immunity. Recent studies have identified inflammatory cell death modalities and their power in providing danger signals to trigger optimal tumor suppression. However, key mediators of inflammatory cell death are preferentially silenced during early tumor immunoediting. Strategies to rejuvenate inflammatory cell death hold great promise for broadening immunotherapy-responsive tumors. In this review, we examine how inflammatory cell death enhances tumor immunogenicity, how it is suppressed during immunoediting, and the potential of harnessing it for improved immunotherapy.

Efficacy and mechanism of action of harmine derivative H-2-104 against Echinococcus granulosus infection in mice

BACKGROUND

Cystic echinococcosis (CE) is a chronic zoonotic parasitic disease caused by the parasite Echinococcus granulosus (E. granulosus). Currently, pharmacologic treatments are limited to albendazole and mebendazole; however, these treatments are associated with significant side effects and limited therapeutic efficacy, highlighting the urgent need for the development of new drugs. Harmine (HM) has been reported to exhibit potent antiparasitic effects, although it is also accompanied by notable neurotoxicity. H-2-104, a derivative of HM obtained through structural modification of its parent nucleus, represents a promising candidate for further investigation. This study aims to assess the in vivo and in vitro efficacy of H-2-104 against E. granulosus and to elucidate the mechanism of action of H-2-104 against CE from a metabolomics perspective.

METHODS

In vitro pharmacodynamics experiments were conducted to assess the inhibitory activity of H-2-104 against E. granulosus protoscoleces (PSCs). Following this, a mouse model of E. granulosus infection was established to explore the inhibitory effects against E. granulosus of H-2-104 at low, medium, and high concentrations. Additionally, non-targeted metabolomic approaches were utilized to analyze the serum and liver samples from mice in the control group, model group, and H-2-104 treatment group with the aim of identifying relevant biomarkers and crucial metabolic pathways involved in the response to H-2-104 treatment.

RESULTS

The in vitro results demonstrated that H-2-104 exhibited significantly superior inhibitory activity against PSCs compared to harmine and albendazole. Morphological observations revealed marked alterations in the ultrastructural characteristics of PSCs treated with H-2-104. In vivo pharmacodynamic studies showed that H-2-104 at a dosage of 100 mg/kg exhibited the highest cyst inhibition rate, which was (73.60 ± 4.71)%. Metabolomics analysis revealed that 64 serum metabolites were significantly altered, primarily involving metabolic pathways such as necroptosis, linoleic acid metabolism, and phenylalanine metabolism. Additionally, 81 liver metabolites were identified with significant differences, mainly involving metabolic pathways like fructose and mannose metabolism, and glycerophospholipid metabolism.

CONCLUSIONS

H-2-104 exhibits significant activity both in vitro and in vivo, suggesting its potential as a promising new drug for the treatment of CE. The anti-CE effects of H-2-104 may be attributed to its regulation of multiple biological pathways, including cell apoptosis, amino acid metabolism, and glucose metabolism.

SERPINI1 serves as a biomarker promoting cell proliferation and invasion in hepatocellular carcinoma

BACKGROUND

SERPINI1 is a protein-coding gene, which has been reported to be related to malignancies, and the encoding protein is a secreted protein. Nevertheless, the specific effect of SERPINI1 on Hepatocellular carcinoma (HCC) remains unclear.

METHODS

The expression level of SERPINI1 in cancers was detected by the Gene Expression Omnibus (GEO) database, the Gene Expression Profiling Interactive Analysis (GEPIA) database and the collected serum of HCC patients. The receiver operating characteristic (ROC) curve and area under curve (AUC) were used to evaluate the diagnostic effectiveness of serum SERPINI1 and the combination of AFP and SERPINI1 for HCC. The Kaplan-Meier (KM) survival was used to evaluate the prognostic capacity of SERPINI1 for HCC in GEPIA database. Furthermore, the correlations between clinicopathological characteristics and the level of serum SERPINI1 were analyzed. Besides, we detected the expression of SERPINI1 in HepG2 by qPCR and western blot, and confirmed the biological function of SERPINI1 through MTT, EdU, wound healing and transwell invasion assay.

RESULTS

The results indicated that the level of SERPINI1 was significantly increased in tissue and serum of HCC patients. ROC analysis displayed that SERPINI1 had a significantly diagnostic value for HCC, the combination of AFP and SERPINI1 gained the higher specificity and sensitivity. The KM survival curves indicated that patients with SERPINI1 overexpression had worse overall survival. Furthermore, we found the positive correlations between serum SERPINI1 level and some clinicopathological characteristics, such as tumor size, differentiation degrees and so on. In addition, in vitro experiments revealed that SERPINI1 could promote the proliferation and invasion of HCC.

CONCLUSIONS

Taken together, our study demonstrates that SERPINI1, which is highly expressed in HCC and closely related to cell proliferation and invasion, may serve as a novel biomarker for diagnosis and prognosis of HCC.

Exceptional Uptake, Limited Protein Expression: Liver Macrophages Lost in Translation of Synthetic mRNA

Most gene therapies exert their actions via manipulation of hepatocytes (parenchymal cells) and the reasons behind the suboptimal performance of synthetic mRNA in non-parenchymal cells (NPC) such as Kupffer cells (KC), and liver macrophages, remain unclear. Here, the spatio-temporal distribution of mRNA encoding enhanced green fluorescent protein (Egfp), siRNA, or both co-encapsulated into lipid nanoparticles (LNP) in the liver in vivo using real-time intravital imaging is investigated. Although both KC and hepatocytes demonstrate comparable high and rapid uptake of mRNA-LNP and siRNA-LNP in vivo, the translation of Egfp mRNA occurs exclusively in hepatocytes during intravital imaging. Despite attempts such as inhibiting intracellular ribonuclease, substituting uridine bases in mRNA with pseudouridine, and using a different ionizable lipid in the LNP mixture, no substantial increase in Egfp translation by NPC is possible. The investigation reveals that hepatocytes, which are distinct from other liver cells due to their polyploidy, exhibit significantly elevated levels of total RNA and protein, along with a higher proportion of ribosomal protein per individual cell. Consequently, fundamental cellular differences account for the low mRNA translation observed in NPC. The findings therefore suggest that cellular biology imposes a natural limitation on synthetic mRNA translation that is strongly influenced by cellular ploidy.

Cell Death and Survival Mechanisms in Cholangiocarcinogenesis

Cholangiocarcinoma (CCA) and other liver cancer subtypes often develop in damaged organs. Physiological agents or extrinsic factors such as toxins can induce cell death in such tissues, triggering compensatory proliferation and inflammation. Depending on extracellular and intracellular factors, different mechanisms such as apoptosis, necroptosis, ferroptosis, or autophagy can be triggered. Each of these mechanisms can lead to pro-tumorigenic or anti-tumorigenic events within a cell or through regulation of the microenvironment. However, the exact role of each cell death mechanism in CCA onset, progression, and treatment is not well known. Here, we summarize current knowledge of different cell death and survival mechanisms in patients with CCA and preclinical CCA research. We discuss cell death-related drugs with relevance to CCA treatment and how they could be used in the future to improve targeted CCA therapy.

Regulation of KIF23 by miR-107 controls replicative tumor cell fitness in mouse and human hepatocellular carcinoma

BACKGROUND & AIMS

In hepatocellular carcinoma (HCC), successful translation of experimental targets identified in mouse models to human patients has proven challenging. In this study, we used a comprehensive transcriptomic approach in mice to identify novel potential targets for therapeutic intervention in humans.

METHODS

We analyzed combined genome-wide miRNA and mRNA expression data in three pathogenically distinct mouse models of liver cancer. Effects of target genes on hepatoma cell fitness were evaluated by proliferation, survival and motility assays. TCGA and GEO databases, in combination with tissue microarrays, were used to validate the mouse targets and their impact on human HCC prognosis. Finally, the functional effects of the identified targets on tumorigenesis and tumor therapy were tested in hydrodynamic tail vein injection-based preclinical HCC models in vivo.

RESULTS

The expression of miR-107 was found to be significantly reduced in mouse models of liver tumors of various etiologies and in cohorts of humans with HCC. Overexpression of miR-107 or inhibition of its novel target kinesin family member 23 (Kif23) significantly reduced proliferation by interfering with cytokinesis, thereby controlling survival and motility of mouse and human hepatoma cells. In humans, KIF23 expression was found to be a prognostic marker in liver cancer, with high expression associated with poor prognosis. Hydrodynamic tail vein injection of vectors carrying either pre-miR-107 or anti-Kif23 shRNA inhibited the development of highly aggressive c-Myc-NRAS-induced liver cancers in mice.

CONCLUSIONS

Disruption of the miR-107/Kif23 axis inhibited hepatoma cell proliferation in vitro and prevented oncogene-induced liver cancer development in vivo, offering a novel potential avenue for the treatment of HCC in humans.

IMPACT AND IMPLICATIONS

Our study revealed the central role of the miR-107/KIF23 axis in controlling tumor cell fitness and hepatocellular carcinoma progression. The results demonstrate that the overexpression of miR-107 or silencing of its target, KIF23, markedly suppresses the proliferation, survival, and motility of human and mouse hepatoma cells. In this work, we demonstrate that the disruption of miR-107/Kif23 signaling effectively protects mice from an aggressive form of oncogene-induced liver cancer in vivo, implying that targeting miR-107/KIF23 might be a novel therapeutic approach for hepatocellular carcinoma in humans.

Noncanonical feedback loop between "RIP3-MLKL" and "4EBP1-eIF4E" promotes neuronal necroptosis

Stroke is a leading risk factor for disability and death. Necroptosis is involved in stroke pathogenesis. However, the molecular mechanisms underlying necroptosis in stroke remain unclear. The mammalian target of rapamycin complex 1 (mTORC1) modulates necroptosis in the gut epithelium. Eukaryotic translation initiation factor 4E (eIF4E)-binding protein-1 (4EPB1) is one of the main downstream molecules of mTORC1. This study addresses the role of the 4EBP1-eIF4E pathway in necroptosis. The 4EBP1-eIF4E pathway was found to be activated in both necroptotic HT-22 and mouse middle cerebral artery occlusion (MCAO) models. Functionally, 4EBP1 overexpression, eIF4E knockdown, and eIF4E inhibition suppressed necroptosis, respectively. Furthermore, a positive feedback circuit was observed between the 4EBP1-eIF4E and receptor-interacting protein-3 (RIP3)-mixed lineage kinase domain-like protein (MLKL) pathways, in which RIP3-MLKL activates the 4EBP1-eIF4E pathway by degrading 4EBP1 and activating eIF4E. This in turn enhanced RIP3-MLKL pathway activation. The eIF4E activation derived from this loop may stimulate cytokine production, which is a key factor associated with necroptosis. Finally, using a mouse MCAO model, the application of eIF4E, RIP3, and MLKL inhibitors was found to have a regulatory mechanism similar to that in the in vitro study, reducing the infarct volume and improving neurological function in MCAO mice.

New insights into pulmonary arterial hypertension: interaction between PANoptosis and perivascular inflammatory responses

Pulmonary arterial hypertension (PAH) is a heterogeneous disease characterized by various etiologies, with pulmonary vascular remodeling recognized as a main pathological change. Currently, it is widely accepted that vascular remodeling is closely associated with abnormal pulmonary vascular cell death and perivascular inflammation. The simultaneous activation of various pulmonary vascular cell death leads to immune cell adhesion and inflammatory mediator releases; And in turn, the inflammatory response may also trigger cell death and jointly promote the progression of vascular remodeling. Recently, PANoptosis has been identified as a phenomenon that describes the simultaneous activation and interaction of multiple forms of programmed cell death (PCD). Therefore, the relationship between PANoptosis and inflammation in PAH warrants further investigation. This review examines the mechanisms underlying apoptosis, necroptosis, pyroptosis, and inflammatory responses in PAH, with a focus on PANoptosis and its interactions with inflammation. And it aims to elucidate the significance of this emerging form of cell death and inflammation in the pathophysiology of PAH and to explore its potential as a therapeutic target.

A decision point between transdifferentiation and programmed cell death priming controls KRAS-dependent pancreatic cancer development

KRAS-dependent acinar-to-ductal metaplasia (ADM) is a fundamental step in the development of pancreatic ductal adenocarcinoma (PDAC), but the involvement of cell death pathways remains unclear. Here, we show that key regulators of programmed cell death (PCD) become upregulated during KRAS-driven ADM, thereby priming transdifferentiated cells to death. Using transgenic mice and primary cell and organoid cultures, we show that transforming growth factor (TGF)-β-activated kinase 1 (TAK1), a kinase regulating cell survival and inflammatory pathways, prevents the elimination of transdifferentiated cells through receptor-interacting protein kinase 1 (RIPK1)-mediated apoptosis and necroptosis, enabling PDAC development. Accordingly, pharmacological inhibition of TAK1 induces PCD in patient-derived PDAC organoids. Importantly, cell death induction via TAK1 inhibition does not appear to elicit an overt injury-associated inflammatory response. Collectively, these findings suggest that TAK1 supports cellular plasticity by suppressing spontaneous PCD activation during ADM, representing a promising pharmacological target for the prevention and treatment of PDAC.

Molecular mechanisms in liver repair and regeneration: from physiology to therapeutics

Liver repair and regeneration are crucial physiological responses to hepatic injury and are orchestrated through intricate cellular and molecular networks. This review systematically delineates advancements in the field, emphasizing the essential roles played by diverse liver cell types. Their coordinated actions, supported by complex crosstalk within the liver microenvironment, are pivotal to enhancing regenerative outcomes. Recent molecular investigations have elucidated key signaling pathways involved in liver injury and regeneration. Viewed through the lens of metabolic reprogramming, these pathways highlight how shifts in glucose, lipid, and amino acid metabolism support the cellular functions essential for liver repair and regeneration. An analysis of regenerative variability across pathological states reveals how disease conditions influence these dynamics, guiding the development of novel therapeutic strategies and advanced techniques to enhance liver repair and regeneration. Bridging laboratory findings with practical applications, recent clinical trials highlight the potential of optimizing liver regeneration strategies. These trials offer valuable insights into the effectiveness of novel therapies and underscore significant progress in translational research. In conclusion, this review intricately links molecular insights to therapeutic frontiers, systematically charting the trajectory from fundamental physiological mechanisms to innovative clinical applications in liver repair and regeneration.

Investigating the Effect and Potential Mechanism of Rhamnetin 3-O-α-Rhamnoside on Acute Liver Injury In Vivo and In Vitro

Background/Objectives: Rhamnetin 3-O-α-rhamnoside (ARR) is a major flavonoid of the herb Loranthus tanakae Franch. & Sav., which has been used for treating liver diseases in China. However, the protective effect of ARR on the liver has not been reported. Methods: Zebrafish larvae were used as a visual animal model, and liver injury was induced by thioacetamide (TAA) for an acute liver injury (ALI) model. The hepatoprotective activity of ARR was evaluated by assessing liver morphology, liver function indices, oxidative stress, and the mRNA expression levels of inflammation-related genes in the zebrafish model. Additionally, the ROS level, inflammatory factors, and protein expression related to the IKKβ/NF-κB signaling pathway were measured to investigate a potential mechanism of ARR in HepG2 cells. Results: ARR ameliorated TAA-induced growth retardation, reduced liver injury phenotypes, and decreased oxidative stress in the zebrafish. ARR was also able to lower ROS levels in HepG2 cells, effectively inhibit the overactivation of the IKKβ/NF-κB signaling pathway in pathological conditions, inhibit NF-κB p65 translocation from the cytoplasm to the nucleus, and reduce the release of intracellular inflammatory factors. Conclusions: ARR showed significant protective activity against TAA-induced liver injury in in vivo and in vitro models, and its potential mechanism was closely related to the IKKβ/NF-κB signaling pathway.

The interplay between cell death and senescence in cancer

Cellular senescence is a state of permanent proliferative arrest that occurs in response to DNA damage-inducing endogenous and exogenous stresses, and is often accompanied by dynamic molecular changes such as a senescence-associated secretory phenotype (SASP). Accumulating evidence indicates that age-associated increases in the upstream and downstream signals of regulated cell death, including apoptosis, necroptosis, pyroptosis, and ferroptosis, are closely related to the induction of cellular senescence and its phenotype. Furthermore, elevated levels of pro-inflammatory SASP factors with aging can be both a cause and consequence of several cell death modes, suggesting the reciprocal effects of cellular senescence and cells undergoing regulated cell death. Here, we review the critical molecular pathways of the regulated cell death forms and describe the crosstalk between aging-related signals and cancer. In addition, we discuss how targeting regulated cell death could be harnessed in therapeutic interventions for cancer. ABBREVIATIONS: Abbreviations that are not standard in this field are defined at their first occurrence in the article and are used consistently throughout the article.

Pentraxin-3 modulates hepatocyte ferroptosis and the innate immune response in LPS-induced liver injury

The liver plays a crucial role in the immune response during endotoxemia and is one of the critical targets for sepsis-related injuries. As a secretory factor involved in inflammation, pentraxin-3 (PTX3) has been demonstrated to regulate hepatic homeostasis; however, the relationship between PTX3 and cell crosstalk between immune cells and hepatocytes in the liver remains incompletely understood. In this study, we revealed that, compared with WT mice, Ptx3-/- mice with lipopolysaccharide (LPS)-induced endotoxemia exhibited alleviated liver damage, with reduced serum alanine transaminase and aspartate transaminase levels and an improved survival rate. Mechanistically, RNA-Seq and western blot results revealed that Ptx3 knockdown in hepatocytes increased the expression of Tfrc and Ccl20; consequently, Ptx3 deficiency regulated LPS-induced hepatocyte ferroptosis via increased mitochondrial reactive oxygen species and Fe2+ and recruited more macrophages by CCL20/CCR6 axis to be involved in inflammation and the clearance of harmful substances. Moreover, western blot and immunofluorescence staining confirmed that the NF-κB signaling pathway was upregulated upon LPS treatment in Ptx3-knockdown macrophages, promoting phagocytosis and polarization toward M1 macrophages. Collectively, our findings show that the absence of Ptx3 can ameliorate sepsis-induced liver injury by regulating hepatocyte ferroptosis and promote the recruitment and polarization of M1 macrophages. These findings offer a key basis for the development of effective treatments for acute infections.

Targeting caspase-8: a new strategy for combating hepatocellular carcinoma

Hepatocellular carcinoma (HCC) represents the most prevalent form of primary liver cancer and has a high mortality rate. Caspase-8 plays a pivotal role in an array of cellular signaling pathways and is essential for the governance of programmed cell death mechanisms, inflammatory responses, and the dynamics of the tumor microenvironment. Dysregulation of caspase-8 is intricately linked to the complex biological underpinnings of HCC. In this manuscript, we provide a comprehensive review of the regulatory roles of caspase-8 in apoptosis, necroptosis, pyroptosis, and PANoptosis, as well as its impact on inflammatory reactions and the intricate interplay with critical immune cells within the tumor microenvironment, such as tumor-associated macrophages, T cells, natural killer cells, and dendritic cells. Furthermore, we emphasize how caspase-8 plays pivotal roles in the development, progression, and drug resistance observed in HCC, and explore the potential of targeting caspase-8 as a promising strategy for HCC treatment.

A novel necroptosis-related genes signature to predict prognosis and treatment response in bladder cancer

Background

Necroptosis, a form of programmed inflammatory cell death, plays a crucial role in tumor development, necrosis, metastasis, and immune response. This study aimed to explore the role of necroptosis in BLCA and construct a new prognostic model to guide clinical treatment and predict individualized treatment response.

Methods

The transcriptome profiling and the corresponding clinical data of BLCA patients were obtained from the Cancer Genome Atlas database (TCGA) and GEO databases. Univariate, multivariate and LASSO Cox regression analyses were used to identify and construct prognostic features associated with necroptosis. We constructed and validated a prognostic model associated with the patient's overall survival (OS). A nomogram was established to predict the survival rates of BLCA patients. Finally, the correlation between risk scores and tumor immune microenvironment, somatic mutations, immunotherapy, and chemotherapy was comprehensively analyzed.

Results

The study found two distinct NRG clusters and three gene subtypes, with significant differences in pathway enrichment and immune cell infiltration associated with different NRG clusters in the TME. In addition, we screened out six necroptosis prognosis-related genes (including PPP2R3A; CERCAM; PIK3IP1; CNTN1; CES1 and CD96) to construct a risk score prognostic model. Significant differences in overall survival rate, immune cell infiltration status, and somatic mutations existed between the high and low-risk scores in BLCA patients. Finally, drug sensitivity analysis showed that high-risk patients benefited more from immunotherapy and chemotherapy drugs.

Conclusion

This study explores the importance of necroptosis in the prognosis of patients with BLCA, and the prognostic features associated with necroptosis that we identified can serve as new biomarkers to help develop more precise treatment strategies.

RIP1 inhibition reduces chondrocyte apoptosis through downregulating nuclear factor-kappa B signaling in a mouse osteoarthritis model

BACKGROUND

Excessive chondrocyte death is a critical player in the process of osteoarthritis (OA). The present study was aimed to study the role of receptor-interacting serine/threonine kinase (RIP) 1-mediated signaling for programmed cell death in OA.

METHODS

In the present study, RIP1 protein expression was evaluated in mouse OA cartilage and cultured primary murine chondrocytes exposed to tumor necrosis factor-alpha (TNF-α). Protein expression involved in necroptosis and apoptosis and chondrocyte-derived extracellular matrix were examined. Inhibition of RIP1 was conducted using the RNAi technique and pharmacological inhibition. Western blot, immunohistochemistry, and immunofluorescence examination were applied.

RESULTS

The protein presence of RIP1, but not RIP3, was increased in the mouse OA tissue and cultured chondrocytes exposed to TNF-α. Knockdown of RIP1 increased protein expression of collagen II and sex-determining region Y-box transcription factor 9, and reduced protein expression of matrix metallopeptidases 13 and a disintegrin and metalloproteinase with thrombospondin motifs 5. Inhibition of RIP1 reduced the phosphorylated NF-κB signals, decreased cell apoptosis, and restored extracellular matrix expression in cultured chondrocytes. Both RNAi and pharmacological inhibition of RIP1 decelerated the progress of OA in mice.

CONCLUSION

RIP1 regulates chondrocyte apoptosis through NF-κB signaling. Inhibition of RIP1 provides a novel therapeutic approach for OA therapy.

Whole-Tumor Clearing and Imaging of Intratumor Microbiota in Three Dimensions with miCDaL Strategy

Acquiring detailed spatial information about intratumor microbiota in situ is challenging, which leaves 3D distributions of microbiota within entire tumors largely unexplored. Here, a modified iDISCO-CUBIC tissue clearing and D-amino acid microbiome labeling-based (miCDaL) strategy are proposed, that integrates microbiota in situ labeling, tissue clearing, and whole-mount tissue imaging to enable 3D visualization of indigenous intratumor microbiota. Leveraging whole-mount spatial resolution and centimeter-scale imaging depth, the 3D biogeography of microbiota is successfully charted across various tumors at different developmental stages, providing quantitative spatial insights in relation to host tumors. By incorporating an immunostaining protocol, 3D imaging of the immunologic microenvironment is achieved in both murine and human mammary tumors that is previously assumed to be bacteria-free. Notably, immune infiltrates, including T cells and NK cells, and tertiary lymphoid structures are conspicuously absent in bacteria-colonized regions. This 3D imaging strategy for mapping Indigenous intratumor microbiota offers valuable insights into host-microbiota interactions.

Don't fear the reaper: The role of regulated cell death in tumorigenesis and BH3-mimetics for cancer therapy

From its earliest characterization, it has been recognized that there is a role for regulated (programmed) cell death in cancer. As our understanding of the different types of programmed cell death processes and their molecular control has advanced, so have the technologies that allow us to manipulate these processes to, for example, fight against cancer. In this review, we describe the roles of the different forms of regulated cell death in the development of cancer as well as their potential therapeutic exploitation. In that vein, we explore the development and use of BH3-mimetics, a unique class of drugs that can directly activate the apoptotic cell death machinery to treat cancer. Finally, we address key challenges that face the field to improve the use of these therapeutics and the efforts that are being undertaken to do so.

Nanomaterial-Mediated Delivery of MLKL Plasmids Sensitizes Tumors to Immunotherapy and Reduces Metastases

Cancer immunotherapy has emerged as a promising approach for the induction of an antitumor response. While immunotherapy response rates are very high in some cancers, the efficacy against solid tumors remains limited caused by the presence of an immunosuppressive tumor microenvironment. Induction of immunogenic cell death (ICD) in the tumor can be used to boost immunotherapy response in solid cancers by eliciting the release of immune-stimulatory components. However, the delivery of components inducing ICD to tumor sites remains a challenge. Here, a novel delivery method is described for antitumor therapy based on MLKL (Mixed Lineage Kinase Domain-Like), a key mediator of necroptosis and inducer of ICD. A novel highly branched poly (β-amino ester)s (HPAEs) system is designed to efficiently deliver MLKL plasmid DNA to the tumor with consequent enhancement of immune antigen presentation for T cell responses in vitro, and improved antitumor response and prolonged survival in tumor-bearing mice. Combination of the therapy with anti-PD-1 treatment revealed significant changes in the composition of the tumor microenvironment, including increased infiltration of CD8+ T cells and tumor-associated lymphocytes. Overall, the HPAEs delivery system can enhance MLKL-based cancer immunotherapy and promote antitumor immune responses, providing a potential treatment to boost cancer immunotherapies.

Role of gasotransmitters in necroptosis

Gasotransmitters are endogenous gaseous signaling molecules that can freely pass through cell membranes and transmit signals between cells, playing multiple roles in cell signal transduction. Due to extensive and ongoing research in this field, we have successfully identified many gasotransmitters so far, among which nitric oxide, carbon monoxide, and hydrogen sulfide are best studied. Gasotransmitters are implicated in various diseases related to necroptosis, such as cardiovascular diseases, inflammation, ischemia-reperfusion, infectious diseases, and neurological diseases. However, the mechanisms of their effects on necroptosis are not fully understood. This review focuses on endogenous gasotransmitter synthesis and metabolism and discusses their roles in necroptosis, aiming to offer new insights for the therapeutic approaches to necroptosis-associated diseases.

Inhibitors identify an auxiliary role for mTOR signalling in necroptosis execution downstream of MLKL activation

Necroptosis is a lytic and pro-inflammatory form of programmed cell death executed by the terminal effector, the MLKL (mixed lineage kinase domain-like) pseudokinase. Downstream of death and Toll-like receptor stimulation, MLKL is trafficked to the plasma membrane via the Golgi-, actin- and microtubule-machinery, where activated MLKL accumulates until a critical lytic threshold is exceeded and cell death ensues. Mechanistically, MLKL's lytic function relies on disengagement of the N-terminal membrane-permeabilising four-helix bundle domain from the central autoinhibitory brace helix: a process that can be experimentally mimicked by introducing the R30E MLKL mutation to induce stimulus-independent cell death. Here, we screened a library of 429 kinase inhibitors for their capacity to block R30E MLKL-mediated cell death, to identify co-effectors in the terminal steps of necroptotic signalling. We identified 13 compounds - ABT-578, AR-A014418, AZD1480, AZD5363, Idelalisib, Ipatasertib, LJI308, PHA-793887, Rapamycin, Ridaforolimus, SMI-4a, Temsirolimus and Tideglusib - each of which inhibits mammalian target of rapamycin (mTOR) signalling or regulators thereof, and blocked constitutive cell death executed by R30E MLKL. Our study implicates mTOR signalling as an auxiliary factor in promoting the transport of activated MLKL oligomers to the plasma membrane, where they accumulate into hotspots that permeabilise the lipid bilayer to cause cell death.

IFN-γ stimulates Paneth cell secretion through necroptosis mTORC1 dependent

Immune mediators affect multiple biological functions of intestinal epithelial cells (IECs) and, like Paneth and Paneth-like cells, play an important role in intestinal epithelial homeostasis. IFN-γ a prototypical proinflammatory cytokine disrupts intestinal epithelial homeostasis. However, the mechanism underlying the process remains unknown. In this study, using in vivo and in vitro models we demonstrate that IFN-γ is spontaneously secreted in the small intestine. Furthermore, we observed that this cytokine stimulates mitochondrial activity, ROS production, and Paneth and Paneth-like cell secretion. Paneth and Paneth-like secretion downstream of IFN-γ, as identified here, is mTORC1 and necroptosis-dependent. Thus, our findings revealed that the pleiotropic function of IFN-γ also includes the regulation of Paneth cell function in the homeostatic gut.

Intricate interplay between cell metabolism and necroptosis regulation in metabolic dysfunction-associated steatotic liver disease: A narrative review

Metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as non-alcoholic fatty liver disease (NAFLD), encompasses a progressive spectrum of liver conditions, ranging from steatosis to metabolic dysfunction-associated steatohepatitis, characterised by hepatocellular death and inflammation, potentially progressing to cirrhosis and/or liver cancer. In both experimental and human MASLD, necroptosis-a regulated immunogenic necrotic cell death pathway-is triggered, yet its exact role in disease pathogenesis remains unclear. Noteworthy, necroptosis-related signalling pathways are emerging as key players in metabolic reprogramming, including lipid and mitochondrial metabolism. Additionally, metabolic dysregulation is a well-established contributor to MASLD development and progression. This review explores the intricate interplay between cell metabolism and necroptosis regulation and its impact on MASLD pathogenesis. Understanding these cellular events may offer new insights into the complexity of MASLD pathophysiology, potentially uncovering therapeutic opportunities and unforeseen metabolic consequences of targeting necroptosis.

Nanomedicine-induced programmed cell death in cancer therapy: mechanisms and perspectives

The balance of programmed cell death (PCD) mechanisms, including apoptosis, autophagy, necroptosis and others, is pivotal in cancer progression and treatment. Dysregulation of these pathways results in uncontrolled cell growth and resistance to conventional therapies. Nanomedicine offers a promising solution in oncology through targeted drug delivery enabling precise targeting of cancer cells while preserving healthy tissues. This approach reduces the side effects of traditional chemotherapy and enhances treatment efficacy by engaging PCD pathways. We details each PCD pathway, their mechanisms, and innovative nanomedicine strategies to activate these pathways, thereby enhancing therapeutic specificity and minimizing harm to healthy tissues. The precision of nanotechnology in targeting PCD pathways promises significant improvements in cancer treatment outcomes. This synergy between nanotechnology and targeted PCD activation could lead to more effective and less toxic cancer therapies, heralding a new era in cancer treatment.

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.

Role of albumin in the metabolism and excretion of ochratoxin A

Ochratoxin A (OTA) is known to be strongly bound to serum albumin, but it remains unknown how albumin affects its metabolism and kinetics. To close this gap, we used a mouse model, where heterozygous albumin deletion reduces serum albumin to concentrations similar to hypoalbuminemic patients and completely eliminates albumin by a homozygous knockout. OTA and its potential metabolites (OTα, 4-OH-OTA, 7'-OH-OTA, OTHQ, OP-OTA, OTB-GSH, OTB-NAC, OTB) were time-dependently analyzed in plasma, bile, and urine by LC-MS/MS and were compared to previously published hepatotoxicity and nephrotoxicity data. Homozygous albumin deletion strongly accelerated plasma clearance as well as biliary and urinary excretion of the parent compound and its hydroxylation products. Decreasing albumin in mice by the heterozygous and even more by the homozygous knockout leads to an increase in the parent compound in urine which corresponded to increased nephrotoxicity. The role of albumin in OTA-induced hepatotoxicity is more complex, since heterozygous but not homozygous nor wild-type mice showed a strong biliary increase in the toxic open lactone OP-OTA. Correspondingly, OTA-induced hepatotoxicity was higher in heterozygous than in wild-type and homozygous animals. We present evidence that albumin-mediated retention of OTA in hepatocytes is required for formation of the toxic OP-OTA, while complete albumin elimination leads to rapid biliary clearance of OTA from hepatocytes with less formation of OP-OTA. In conclusion, albumin has a strong influence on metabolism and toxicity of OTA. In hypoalbuminemia, the parent OTA is associated with increased nephrotoxicity and the open lactone with increased hepatotoxicity.

Necroptosis in immunity, tissue homeostasis, and cancer

Immune and tissue homeostasis is achieved through balancing signals that regulate cell survival, proliferation, and cell death. Recent studies indicate that certain cell death programs can stimulate inflammation and are often referred as 'immunogenic cell death' (ICD). ICD is a double-edged sword that can confer protection against pathogen infection but also cause tissue damage. Necroptosis is a key ICD module that has been shown to participate in host defense against pathogen infection, tissue homeostasis, and cancer response to immunotherapy. Here, we will review recent findings on the regulation of necroptosis signaling and its role in pathogen infection, tissue homeostasis, and cancer.

Hepatocyte programmed cell death: the trigger for inflammation and fibrosis in metabolic dysfunction-associated steatohepatitis

By replacing and removing defective or infected cells, programmed cell death (PCD) contributes to homeostasis maintenance and body development, which is ubiquitously present in mammals and can occur at any time. Besides apoptosis, more novel modalities of PCD have been described recently, such as necroptosis, pyroptosis, ferroptosis, and autophagy-dependent cell death. PCD not only regulates multiple physiological processes, but also participates in the pathogenesis of diverse disorders, including metabolic dysfunction-associated steatotic liver disease (MASLD). MASLD is mainly classified into metabolic dysfunction-associated steatotic liver (MASL) and metabolic dysfunction-associated steatohepatitis (MASH), and the latter putatively progresses to cirrhosis and hepatocellular carcinoma. Owing to increased incidence and obscure etiology of MASH, its management still remains a tremendous challenge. Recently, hepatocyte PCD has been attracted much attention as a potent driver of the pathological progression from MASL to MASH, and some pharmacological agents have been proved to exert their salutary effects on MASH partly via the regulation of the activity of hepatocyte PCD. The current review recapitulates the pathogenesis of different modalities of PCD, clarifies the mechanisms underlying how metabolic disorders in MASLD induce hepatocyte PCD and how hepatocyte PCD contributes to inflammatory and fibrotic progression of MASH, discusses several signaling pathways in hepatocytes governing the execution of PCD, and summarizes some potential pharmacological agents for MASH treatment which exert their therapeutic effects partly via the regulation of hepatocyte PCD. These findings indicate that hepatocyte PCD putatively represents a new therapeutic point of intervention for MASH.

Intravital imaging: dynamic insights into liver immunity in health and disease

Inflammation is a critical component of most acute and chronic liver diseases. The liver is a unique immunological organ with a dense vascular network, leading to intense crosstalk between tissue-resident immune cells, passenger leucocytes and parenchymal cells. During acute and chronic liver diseases, the multifaceted immune response is involved in disease promoting and repair mechanisms, while upholding core liver immune functions. In recent years, single-cell technologies have unravelled a previously unknown heterogeneity of immune cells, reshaping the complexity of the hepatic immune response. However, inflammation is a dynamic biological process, encompassing various immune cells, orchestrated in temporal and spatial dimensions, and driven by multiorgan signals. Intravital microscopy (IVM) has emerged as a powerful tool to investigate immunity by visualising the dynamic interplay between different immune cells and their surroundings within a near-natural environment. In this review, we summarise the experimental considerations to perform IVM and highlight recent technological developments. Furthermore, we outline the unique contributions of IVM to our understanding of liver immunity. Through the lens of liver disease, we discuss novel immune-mediated disease mechanisms uncovered by imaging-based studies.

Necroptosis plays a role in TL1A-induced airway inflammation and barrier damage in asthma

BACKGROUND

Airway epithelial cell (AEC) necroptosis contributes to airway allergic inflammation and asthma exacerbation. Targeting the tumor necrosis factor-like ligand 1 A (TL1A)/death receptor 3 (DR3) axis has a therapeutic effect on asthmatic airway inflammation. The role of TL1A in mediating necroptosis of AECs challenged with ovalbumin (OVA) and its contribution to airway inflammation remains unclear.

METHODS

We evaluated the expression of the receptor-interacting serine/threonine-protein kinase 3(RIPK3) and the mixed lineage kinase domain-like protein (MLKL) in human serum and lung, and histologically verified the level of MLKL phosphorylation in lung tissue from asthmatics and OVA-induced mice. Next, using MLKL knockout mice and the RIPK3 inhibitor GSK872, we investigated the effects of TL1A on airway inflammation and airway barrier function through the activation of necroptosis in experimental asthma.

RESULTS

High expression of necroptosis marker proteins was observed in the serum of asthmatics, and necroptosis was activated in the airway epithelium of both asthmatics and OVA-induced mice. Blocking necroptosis through MLKL knockout or RIPK3 inhibition effectively attenuated parabronchial inflammation, mucus hypersecretion, and airway collagen fiber accumulation, while also suppressing type 2 inflammatory factors secretion. In addition, TL1A/ DR3 was shown to act as a death trigger for necroptosis in the absence of caspases by silencing or overexpressing TL1A in HBE cells. Furthermore, the recombinant TL1A protein was found to induce necroptosis in vivo, and knockout of MLKL partially reversed the pathological changes induced by TL1A. The necroptosis induced by TL1A disrupted the airway barrier function by decreasing the expression of tight junction proteins zonula occludens-1 (ZO-1) and occludin, possibly through the activation of the NF-κB signaling pathway.

CONCLUSIONS

TL1A-induced airway epithelial necroptosis plays a significant role in promoting airway inflammation and barrier dysfunction in asthma. Inhibition of the TL1A-induced necroptosis pathway could be a promising therapeutic strategy.

Leveraging single-cell sequencing analysis and bulk-RNA sequencing analysis to forecast necroptosis in cutaneous melanoma prognosis

Cutaneous melanoma, a malignancy of melanocytes, presents a significant challenge due to its aggressive nature and rising global incidence. Despite advancements in treatment, the variability in patient responses underscores the need for further research into novel therapeutic targets, including the role of programmed cell death pathways such as necroptosis. The melanoma datasets used for analysis, GSE215120, GSE19234, GSE22153 and GSE65904, were downloaded from the GEO database. The melanoma data from TCGA were downloaded from the UCSC website. Using single-cell sequencing, we assess the heterogeneity of necroptosis in cutaneous melanoma, identifying distinct cell clusters and necroptosis-related gene expression patterns. A combination of 101 machine learning algorithms was employed to construct a necroptosis-related signature (NRS) based on key genes associated with necroptosis. The prognostic value of NRS was evaluated in four cohorts (one TCGA and three GEO cohorts), and the tumour microenvironment (TME) was analysed to understand the relationship between necroptosis, tumour mutation burden (TMB) and immune infiltration. Finally, we focused on the role of key target TSPAN10 in the prognosis, pathogenesis, immunotherapy relevance and drug sensitivity of cutaneous melanoma. Our study revealed significant heterogeneity in necroptosis among melanoma cells, with a higher prevalence in epithelial cells, myeloid cells and fibroblasts. The NRS, developed through rigorous machine learning techniques, demonstrated robust prognostic capabilities, distinguishing high-risk patients with poorer outcomes in all cohorts. Analysis of the TME showed that high NRS scores correlated with lower TMB and reduced immune cell infiltration, indicating a potential mechanism through which necroptosis influences melanoma progression. Finally, TSPAN10 has been identified as a key target for cutaneous melanoma and is highly associated with poor prognosis. The findings highlight the complex role of necroptosis in cutaneous melanoma and introduce the NRS as a novel prognostic tool with potential to guide therapeutic decisions.

GSK'872 Improves Prognosis of Traumatic Brain Injury by Switching Receptor-Interacting Serine/Threonine-Protein Kinase 3-dependent Necroptosis to Cysteinyl Aspartate Specific Proteinase-8-Dependent Apoptosis

BACKGROUND

Traumatic brain injury (TBI) is an important health concern in the society. Previous studies have suggested that necroptosis occurs following TBI. However, the underlying mechanisms and roles of necroptosis are not well understood. In this study, we aimed to assess the role of receptor-interacting serine/threonine-protein kinase 3 (RIP3)-mediated necroptosis after TBI both in vitro and in vivo.

METHODS

We established a cell-stretching injury and mouse TBI model by applying a cell injury controller and controlled cortical impactor to evaluate the relationships among necroptosis, apotosis, inflammation, and TBI both in vitro and in vivo.

RESULTS

The results revealed that necroptosis mediated by RIP1, RIP3, and mixed lineage kinase domain-like protein was involved in secondary TBI. Additionally, protein kinase B (Akt), phosphorylated Akt, mammalian target of rapamycin (mTOR), and phosphorylated mTOR potentially contribute to necroptosis. The inhibition of RIP3 by GSK'872 (a specific inhibitor) blocked necroptosis and reduced the activity of Akt/mTOR, leading to the alleviation of inflammation by reducing the levels of NOD-, LRR- and pyrin domain-containing protein 3. Moreover, the inhibition of RIP3 by GSK'872 promoted the activity of cysteinyl aspartate specific proteinase-8, an enzyme involved in apoptosis and inflammation.

CONCLUSIONS

These data demonstrate that RIP3 inhibition could improve the prognosis of TBI, based on the attenuation of inflammation by switching RIP3-dependent necroptosis to cysteinyl aspartate specific proteinase-8-dependent apoptosis.

Liver macrophages revisited: The expanding universe of versatile responses in a spatiotemporal context

The liver is a vital organ that continuously adapts to a wide and dynamic diversity of self-antigens and xenobiotics. This involves the active contribution of immune cells, particularly by the liver-resident macrophages, the Kupffer cells (KCs), which exert a variety of central functions in liver homeostasis and disease. As such, KCs interact with their microenvironment to shape the hepatic cellular landscape, control gut-derived signal integration, and modulate metabolism. On injury, the rapid recruitment of bone marrow monocyte-derived macrophages alters this status quo and, when unrestrained, drastically compromises liver homeostasis, immune surveillance, and tissue organization. Several factors determine the functional roles of liver macrophages in these processes, such as their ontogeny, activation/polarization profile and, importantly, spatial distribution within the liver. Loss of tolerance and adaptability of the hepatic immune environment may result in persistent inflammation, hepatic fibrosis, cirrhosis, and a tumorigenic niche promoting liver cancer. In this review, we aim at providing the most recent breakthroughs in our understanding of liver macrophage biology, particularly their diversity and adaptability in the hepatic spatiotemporal context, as well as on potential therapeutic interventions that may hold the key to tackling remaining clinical challenges of varying etiologies in hepatology.

An immunohistochemical atlas of necroptotic pathway expression

Necroptosis is a lytic form of regulated cell death reported to contribute to inflammatory diseases of the gut, skin and lung, as well as ischemic-reperfusion injuries of the kidney, heart and brain. However, precise identification of the cells and tissues that undergo necroptotic cell death in vivo has proven challenging in the absence of robust protocols for immunohistochemical detection. Here, we provide automated immunohistochemistry protocols to detect core necroptosis regulators - Caspase-8, RIPK1, RIPK3 and MLKL - in formalin-fixed mouse and human tissues. We observed surprising heterogeneity in protein expression within tissues, whereby short-lived immune barrier cells were replete with necroptotic effectors, whereas long-lived cells lacked RIPK3 or MLKL expression. Local changes in the expression of necroptotic effectors occurred in response to insults such as inflammation, dysbiosis or immune challenge, consistent with necroptosis being dysregulated in disease contexts. These methods will facilitate the precise localisation and evaluation of necroptotic signaling in vivo.

Therapeutic strategies of targeting non-apoptotic regulated cell death (RCD) with small-molecule compounds in cancer

Regulated cell death (RCD) is a controlled form of cell death orchestrated by one or more cascading signaling pathways, making it amenable to pharmacological intervention. RCD subroutines can be categorized as apoptotic or non-apoptotic and play essential roles in maintaining homeostasis, facilitating development, and modulating immunity. Accumulating evidence has recently revealed that RCD evasion is frequently the primary cause of tumor survival. Several non-apoptotic RCD subroutines have garnered attention as promising cancer therapies due to their ability to induce tumor regression and prevent relapse, comparable to apoptosis. Moreover, they offer potential solutions for overcoming the acquired resistance of tumors toward apoptotic drugs. With an increasing understanding of the underlying mechanisms governing these non-apoptotic RCD subroutines, a growing number of small-molecule compounds targeting single or multiple pathways have been discovered, providing novel strategies for current cancer therapy. In this review, we comprehensively summarized the current regulatory mechanisms of the emerging non-apoptotic RCD subroutines, mainly including autophagy-dependent cell death, ferroptosis, cuproptosis, disulfidptosis, necroptosis, pyroptosis, alkaliptosis, oxeiptosis, parthanatos, mitochondrial permeability transition (MPT)-driven necrosis, entotic cell death, NETotic cell death, lysosome-dependent cell death, and immunogenic cell death (ICD). Furthermore, we focused on discussing the pharmacological regulatory mechanisms of related small-molecule compounds. In brief, these insightful findings may provide valuable guidance for investigating individual or collaborative targeting approaches towards different RCD subroutines, ultimately driving the discovery of novel small-molecule compounds that target RCD and significantly enhance future cancer therapeutics.

Necroptosis stimulates interferon-mediated protective anti-tumor immunity

Necroptosis is an inflammatory form of cell suicide that critically depends on the kinase activity of Receptor Interacting Protein Kinase 3 (RIPK3). Previous studies showed that immunization with necroptotic cells conferred protection against subsequent tumor challenge. Since RIPK3 can also promote apoptosis and NF-κB-dependent inflammation, it remains difficult to determine the contribution of necroptosis-associated release of damage-associated molecular patterns (DAMPs) in anti-tumor immunity. Here, we describe a system that allows us to selectively induce RIPK3-dependent necroptosis or apoptosis with minimal NF-κB-dependent inflammatory cytokine expression. In a syngeneic tumor challenge model, immunization with necroptotic cells conferred superior protection against subsequent tumor challenge. Surprisingly, this protective effect required CD4+ T cells rather than CD8+ T cells and is dependent on host type I interferon signaling. Our results provide evidence that death-dependent type I interferon production following necroptosis is sufficient to elicit protective anti-tumor immunity.

Immunogenic cell death in cancer: targeting necroptosis to induce antitumour immunity

Most metastatic cancers remain incurable due to the emergence of apoptosis-resistant clones, fuelled by intratumour heterogeneity and tumour evolution. To improve treatment, therapies should not only kill cancer cells but also activate the immune system against the tumour to eliminate any residual cancer cells that survive treatment. While current cancer therapies rely heavily on apoptosis - a largely immunologically silent form of cell death - there is growing interest in harnessing immunogenic forms of cell death such as necroptosis. Unlike apoptosis, necroptosis generates second messengers that act on immune cells in the tumour microenvironment, alerting them of danger. This lytic form of cell death optimizes the provision of antigens and adjuvanticity for immune cells, potentially boosting anticancer treatment approaches by combining cellular suicide and immune response approaches. In this Review, we discuss the mechanisms of necroptosis and how it activates antigen-presenting cells, drives cross-priming of CD8+ T cells and induces antitumour immune responses. We also examine the opportunities and potential drawbacks of such strategies for exposing cancer cells to immunological attacks.

Acetaminophen overdose causes a breach of the blood-bile barrier in mice but not in rats

Acetaminophen (APAP) is known to cause a breach of the blood-bile barrier in mice that, via a mechanism called futile bile acid (BA) cycling, increases BA concentrations in hepatocytes above cytotoxic thresholds. Here, we compared this mechanism in mice and rats, because both species differ massively in their susceptibility to APAP and compared the results to available human data. Dose and time-dependent APAP experiments were performed in male C57BL6/N mice and Wistar rats. The time course of BA concentrations in liver tissue and in blood was analyzed by MALDI-MSI and LC-MS/MS. APAP and its derivatives were measured in the blood by LC-MS. APAP-induced liver damage was analyzed by histopathology, immunohistochemistry, and by clinical chemistry. In mice, a transient increase of BA in blood and in peri-central hepatocytes preceded hepatocyte death. The BA increase coincided with oxidative stress in liver tissue and a compromised morphology of bile canaliculi and immunohistochemically visualized tight junction proteins. Rats showed a reduced metabolic activation of APAP compared to mice. However, even at very high doses that caused cell death of hepatocytes, no increase of BA concentrations was observed neither in liver tissue nor in the blood. Correspondingly, no oxidative stress was detectable, and the morphology of bile canaliculi and tight junction proteins remained unaltered. In conclusion, different mechanisms cause cell death in rats and mice, whereby oxidative stress and a breach of the blood-bile barrier are seen only in mice. Since transient cholestasis also occurs in human patients with APAP overdose, mice are a clinically relevant species to study APAP hepatotoxicity but not rats.

Delineating the heterogeneity of senescence-induced-functional alterations in hepatocytes

BACKGROUND AND AIM

Cellular senescence of hepatocytes involves permanent cell cycle arrest, disrupted cellular bioenergetics, resistance to cell death, and the release of pro-inflammatory cytokines. This 'zombie-like' state perpetuates harmful effects on tissues and holds potential implications for liver disease progression. Remarkably, senescence exhibits heterogeneity, stemming from two crucial factors: the inducing stressor and the cell type. As such, our present study endeavors to characterize stressor-specific changes in senescence phenotype, its related molecular patterns, and cellular bioenergetics in primary mouse hepatocytes (PMH) and hepatocyte-derived liver organoids (HepOrgs).

METHODS

PMH, isolated by collagenase-perfused mouse liver (C57B6/J; 18-23 weeks), were cultured overnight in William's E-medium supplemented with 2% FBS, L-glutamine, and hepatocyte growth supplements. HepOrgs were developed by culturing cells in a 3D matrix for two weeks. The senescence was induced by DNA damage (doxorubicin, cisplatin, and etoposide), oxidative stress (H2O2, and ethanol), and telomere inhibition (BIBR-1532), p53 activation (nutlin-3a), DNA methyl transferase inhibition (5-azacitidine), and metabolism inhibitors (galactosamine and hydroxyurea). SA-β galactosidase activity, immunofluorescence, immunoblotting, and senescence-associated secretory phenotype (SASP), and cellular bioenergetics were used to assess the senescence phenotype.

RESULTS

Each senescence inducer triggers a unique combination of senescence markers in hepatocytes. All senescence inducers, except hydroxyurea and ethanol, increased SA-β galactosidase activity, the most commonly used marker for cellular senescence. Among the SASP factors, CCL2 and IL-10 were consistently upregulated, while Plasminogen activator inhibitor-1 exhibited global downregulation across all modes of senescence. Notably, DNA damage response was activated by DNA damage inducers. Cell cycle markers were most significantly reduced by doxorubicin, cisplatin, and galactosamine. Additionally, DNA damage-induced senescence shifted cellular bioenergetics capacity from glycolysis to oxidative phosphorylation. In HepOrgs exposed to senescence inducers, there was a notable increase in γH2A.X, p53, and p21 levels. Interestingly, while showing a similar trend, SASP gene expression in HepOrgs was significantly higher compared to PMH, demonstrating a several-fold increase.

CONCLUSION

In our study, we demonstrated that each senescence inducer activates a unique combination of senescence markers in PMH. Doxorubicin demonstrated the highest efficacy in inducing senescence, followed by cisplatin and H2O2, with no impact on apoptosis. Each inducer prompted DNA damage response and mitochondrial dysfunction, independent of MAPK/AKT.

ScRNA-seq reveals novel immune-suppressive T cells and investigates CMV-TCR-T cells cytotoxicity against GBM

BACKGROUND

Glioblastoma (GBM) is a fatal primary brain malignancy in adults. Previous studies have shown that cytomegalovirus (CMV) is a risk factor for tumorigenesis and aggressiveness for glioblastoma. However, little is known about how CMV infection affects immune cells in the tumor microenvironment of GBM. Furthermore, there has been almost no engineered T-cell receptor (TCR)-T targeting CMV for GBM research to date.

METHODS

We evaluated the CMV infection status of patients with GBM's tumor tissue by immune electron microscopy, immunofluorescence, and droplet digital PCR. We performed single-cell RNA sequencing for CMV-infected GBM to investigate the effects of CMV on the GBM immune microenvironment. CellChat was applied to analyze the interaction between cells in the GBM tumor microenvironment. Additionally, we conducted single-cell TCR/B cell receptor (BCR) sequencing and Grouping of Lymphocyte Interactions with Paratope Hotspots 2 algorithms to acquire specific CMV-TCR sequences. Genetic engineering was used to introduce CMV-TCR into primary T cells derived from patients with CMV-infected GBM. Flow cytometry was used to measure the proportion and cytotoxicity status of T cells in vitro.

RESULTS

We identified two novel immune cell subpopulations in CMV-infected GBM, which were bipositive CD68+SOX2+ tumor-associated macrophages and FXYD6+ T cells. We highlighted that the interaction between bipositive TAMs or cancer cells and T cells was predominantly focused on FXYD6+ T cells rather than regulatory T cells (Tregs), whereas, FXYD6+ T cells were further identified as a group of novel immunosuppressive T cells. CMV-TCR-T cells showed significant therapeutic effects on the human-derived orthotopic GBM mice model.

CONCLUSIONS

These findings provided an insight into the underlying mechanism of CMV infection promoting the GBM immunosuppression, and provided a novel potential immunotherapy strategy for patients with GBM.

Evidence of promoting effects of 6:2 Cl-PFESA on hepatocellular carcinoma proliferation in humans: An ideal alternative for PFOS in terms of environmental health?

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are synthetic chemicals, encompassing compounds like perfluorooctane sulfonate (PFOS), which have widespread applications across various industries, including food packaging and firefighting. In recent years, China has increasingly employed 6:2 Cl-PFESA as an alternative to PFOS. Although the association between PFAS exposure and hepatocellular carcinoma (HCC) has been demonstrated, the underlying mechanisms that promote HCC proliferation are uncleared. Therefore, we aimed to investigate the effects and differences of PFOS and 6:2 Cl-PFESA on HCC proliferation through in vivo and in vitro tumor models. Our results reveal that both PFOS and 6:2 Cl-PFESA significantly contribute to HCC proliferation in vitro and in vivo. Exposure led to reduced population doubling times, enlarged cell colony sizes, enhanced DNA synthesis efficiency, and a higher proportion of cells undergoing mitosis. Furthermore, both PFOS and 6:2 Cl-PFES) have been shown to activate the PI3K/AKT/mTOR signaling pathway and inhibit necroptosis. This action consequently enhances the proliferation of HCC cells. Our phenotypic assay findings suggest that the tumorigenic potential of 6:2 Cl-PFESA surpasses that of PFOS; in a subcutaneous tumor model using nude mice, the mean tumor weight for the 6:2 Cl-PFESA-treated cohort was 2.33 times that observed in the PFOS cohort (p < 0.01). Despite 6:2 Cl-PFESA being considered a safer substitute for PFOS, the pronounced effects of this chemical on HCC cell growth warrant a thorough assessment of hepatotoxicity risks linked to its usage.

Integrated data from intravital imaging and HPLC-MS/MS analysis reveal large interspecies differences in AFB1 metabolism in mice and rats

Large interspecies differences between rats and mice concerning the hepatotoxicity and carcinogenicity of aflatoxin B1 (AFB1) are known, with mice being more resistant. However, a comprehensive interspecies comparison including subcellular liver tissue compartments has not yet been performed. In this study, we performed spatio-temporal intravital analysis of AFB1 kinetics in the livers of anesthetized mice and rats. This was supported by time-dependent analysis of the parent compound as well as metabolites and adducts in blood, urine, and bile of both species by HPLC-MS/MS. The integrated data from intravital imaging and HPLC-MS/MS analysis revealed major interspecies differences between rats and mice: (1) AFB1-associated fluorescence persisted much longer in the nuclei of rat than mouse hepatocytes; (2) in the sinusoidal blood, AFB1-associated fluorescence was rapidly cleared in mice, while a time-dependent increase was observed in rats in the first three hours after injection followed by a plateau that lasted until the end of the observation period of six hours; (3) this coincided with a far stronger increase of AFB1-lysine adducts in the blood of rats compared to mice; (4) the AFB1-guanine adduct was detected at much higher concentrations in bile and urine of rats than mice. In both species, the AFB1-glutathione conjugate was efficiently excreted via bile, where it reached concentrations at least three orders of magnitude higher compared to blood. In conclusion, major differences between mice and rats were observed, concerning the nuclear persistence, formation of AFB1-lysine adducts, and the AFB1-guanine adducts.

Gasdermin and MLKL necrotic cell death effectors: Signaling and diseases

Diverse inflammatory conditions, from infections to autoimmune disease, are often associated with cellular damage and death. Apoptotic cell death has evolved to minimize its inflammatory potential. By contrast, necrotic cell death via necroptosis and pyroptosis-driven by membrane-damaging MLKL and gasdermins, respectively-can both initiate and propagate inflammatory responses. In this review, we provide insights into the function and regulation of MLKL and gasdermin necrotic effector proteins and drivers of plasma membrane rupture. We evaluate genetic evidence that MLKL- and gasdermin-driven necrosis may either provide protection against, or contribute to, disease states in a context-dependent manner. These cumulative insights using gene-targeted mice underscore the necessity for future research examining pyroptotic and necroptotic cell death in human tissue, as a basis for developing specific necrotic inhibitors with the potential to benefit a spectrum of pathological conditions.

Cell Death in Liver Disease and Liver Surgery

Cell death is crucial for maintaining tissue balance and responding to diseases. However, under pathological conditions, the surge in dying cells results in an overwhelming presence of cell debris and the release of danger signals. In the liver, this gives rise to hepatic inflammation and hepatocellular cell death, which are key factors in various liver diseases caused by viruses, toxins, metabolic issues, or autoimmune factors. Both clinical and in vivo studies strongly affirm that hepatocyte death serves as a catalyst in the progression of liver disease. This advancement is characterized by successive stages of inflammation, fibrosis, and cirrhosis, culminating in a higher risk of tumor development. In this review, we explore pivotal forms of cell death, including apoptosis, pyroptosis, and necroptosis, examining their roles in both acute and chronic liver conditions, including liver cancer. Furthermore, we discuss the significance of cell death in liver surgery and ischemia-reperfusion injury. Our objective is to illuminate the molecular mechanisms governing cell death in liver diseases, as this understanding is crucial for identifying therapeutic opportunities aimed at modulating cell death pathways.

Inhibition of NF-κB signaling unveils novel strategies to overcome drug resistance in cancers

Drug resistance in cancer remains a major challenge in oncology, impeding the effectiveness of various treatment modalities. The nuclear factor-kappa B (NF-κB) signaling pathway has emerged as a critical player in the development of drug resistance in cancer cells. This comprehensive review explores the intricate relationship between NF-κB and drug resistance in cancer. We delve into the molecular mechanisms through which NF-κB activation contributes to resistance against chemotherapeutic agents, targeted therapies, and immunotherapies. Additionally, we discuss potential strategies to overcome this resistance by targeting NF-κB signaling, such as small molecule inhibitors and combination therapies. Understanding the multifaceted interactions between NF-κB and drug resistance is crucial for the development of more effective cancer treatment strategies. By dissecting the complex signaling network of NF-κB, we hope to shed light on novel therapeutic approaches that can enhance treatment outcomes, ultimately improving the prognosis for cancer patients. This review aims to provide a comprehensive overview of the current state of knowledge on NF-κB and its role in drug resistance, offering insights that may guide future research and therapeutic interventions in the fight against cancer.