Chemotherapy-induced pyroptosis is mediated by BAK/BAX-caspase-3-GSDME pathway and inhibited by 2-bromopalmitate

Targeting programmed cell death pathways in gastric cancer: a focus on pyroptosis, apoptosis, necroptosis and PANoptosis

Gastric cancer (GC) is recognized as one of the most prevalent and serious malignancies, distinguished by its high incidence and fatality rates. Given the considerable mortality rate associated with GC, it is imperative to clarify the related pathways of GC development and further identify feasible targets for rational targeted therapy. Accumulating evidence reveals that programmed cell death (PCD) is a crucial element in both the progression and treatment of cancer. Pyroptosis, apoptosis, and necroptosis are three well-studied types of PCD, and a link between them and GC has been established in recent studies. PANoptosis, a comparatively novel type of PCD, shares key traits with pyroptosis, apoptosis, and necroptosis, yet cannot be entirely illustrated by any single model. PANoptosis has been discovered to exert an impact on multiple diseases, including cancer, infections, and inflammatory conditions, consequently offering novel perceptions into the progression and treatment of GC. This review seeks to encapsulate the emerging roles and therapeutic potential of pyroptosis, apoptosis, necroptosis, and PANoptosis in GC, laying the groundwork for the advancement of innovative treatment methods that target important signaling pathways connected with these four forms of PCD.

Novel one-/two-photon excited β-carboline/quinolinium photosensitizers for hypoxia-resistant tumor photodynamic therapy through apoptosis and necrosis

Photodynamic therapy (PDT) represents an innovative modality that employs photosensitizer for the treatment of tumors, dermatological conditions, and vascular disorders. Herein, a series of novel photosensitizers 2a-e were designed and synthesized by incorporating quinolinium into the β-carboline. In particular, photosensitizer 2d generated a large amount of type-I/-II active oxygen species, including 1O2, •O2-, and •OH under one-/two-photon excitation. Furthermore, 2d effectively overcame the tumor hypoxic microenvironment and exhibited strong one-/two-photon photodynamic activities against HT29 cells (IC50s = 0.18-0.56 μM, PIs = 88-263). Additionally, 2d could significantly induce cancer cell apoptosis via reducing Bcl-2 and increasing Bax/Cleaved-caspase-3, and simultaneously promote programmed necrosis through boosting P-MLKL and P-RIPK1/3 expression. In vivo experiments substantiated that 2d powerfully suppressed colonic tumor growth under one-/two-photon irradiation (suppression rates 77-91 %). Therefore, this work may provide an effective approach for designing novel β-carboline/quinolinium photosensitizers and present a promising prospect in the field of one-/two-photon tumor photodynamic therapy.

Toxicological Mechanism of Triptolide-Induced Liver Injury

This study aimed to investigate the hepatotoxicity of triptolide (TRI) and its mechanism of action. The TRI-liver injury-pyroptosis association and the possible action targets were analyzed through network pharmacology, the molecular-protein docking analysis was conducted by the molecular docking method, and the binding mode between TRI and candidate targets was analyzed with dynamics simulation. In addition, the mouse model of TRI-induced liver injury was constructed in vitro to examine the influence of TRI on liver function. The expression levels of inflammatory factors were detected by ELISA, while pathological analysis was conducted by H&E staining and histochemical staining. As figured out from the network pharmacology analysis results, Caspase-3 might be the major action target of TRI, which was verified by molecular docking and dynamics simulation. Besides, the in vitro experimental results demonstrated that TRI induced liver injury in mice, enhanced the tissue inflammatory response. Caspase-3 may be the major target of TRI in liver injury, and TRI can mediate pyroptosis and tissue inflammatory response through Caspase-3 to induce acute liver injury.

Cleavage of CAD by caspase-3 determines the cancer cell fate during chemotherapy

Metabolic heterogeneity resulting from the intra-tumoral heterogeneity mediates massive adverse outcomes of tumor therapy, including chemotherapeutic resistance, but the mechanisms inside remain largely unknown. Here, we find that the de novo pyrimidine synthesis pathway determines the chemosensitivity. Chemotherapeutic drugs promote the degradation of cytosolic Carbamoyl-phosphate synthetase II, Aspartate transcarbamylase, and Dihydroorotase (CAD), an enzyme that is rate-limiting for pyrimidine synthesis, leading to apoptosis. We also find that CAD needs to be cleaved by caspase-3 on its Asp1371 residue, before its degradation. Overexpressing CAD or mutating Asp1371 to block caspase-3 cleavage confers chemoresistance in xenograft and Cldn18-ATK gastric cancer models. Importantly, mutations related to Asp1371 of CAD are found in tumor samples that failed neoadjuvant chemotherapy and pharmacological targeting of CAD-Asp1371 mutations using RMY-186 ameliorates chemotherapy efficacy. Our work reveals the vulnerability of de novo pyrimidine synthesis during chemotherapy, highlighting CAD as a promising therapeutic target and biomarker.

Decoding TMAO in the Gut-Organ Axis: From Biomarkers and Cell Death Mechanisms to Therapeutic Horizons

The gut microbiota and its metabolites are bi-directionally associated with various human illnesses, which has received extensive attention. Trimethylamine N-oxide (TMAO) is a gut microbiota metabolite produced in the liver, which may serve the role of an "axis" connecting the gut and host organs. TMAO levels are significantly higher in the blood of individuals with cardiovascular, renal, neurological, and metabolic diseases. Endothelial cells are crucial for regulating microcirculation and maintaining tissue and organ barriers and are widely recognized as target cells for TMAO. TMAO not only induces endothelial dysfunction but also acts on various cell types, such as endothelial cells, epithelial cells, vascular smooth muscle cells, nerve cells, and pancreatic cells, triggering multiple cell death mechanisms, including necrosis and programmed cell death, thereby influencing host health. This paper thoroughly covers the origins, production, and metabolic pathways of TMAO, emphasizing its importance in the early detection and prognosis of human diseases in the "Gut-Organ" axis, as well as its mechanisms of influence on human diseases, particularly the cross-talk with cell death. Furthermore, we cover recent advances in treating human diseases by regulating gut microbiota structure and enzyme activity to influence TMAO metabolism and reduce TMAO levels, including the use of probiotics, prebiotics, antibiotics, anti-inflammatory drugs, antiplatelet drugs, hypoglycemic drugs, lipid-lowering drugs, and natural products.

New advances of natural products in non-small cell lung cancer: From mechanisms to therapies

ETHNOPHARMACOLOGICAL RELEVANCE

With the rise of immunotherapy, the treatment approach for non-small cell lung cancer (NSCLC) has undergone revolutionary changes. However, the prognosis for NSCLC patients has not been significantly improved due to the development of acquired drug resistance. Therefore, there is an urgent need to develop new and more effective drugs for treating NSCLC or improving tumor treatment resistance. Traditional Chinese medicine (TCM) has been gradually incorporated into the combined treatment of NSCLC. Its active components (also known as natural products) exhibit novel structures, multi-target effects, diverse pathways, minimal toxicity, and varied biological activities, which play a therapeutic role in various diseases. Thus, natural products hold great potential for future clinical applications.

AIM OF THE STUDY

Screening main traditional plants widely used in NSCLC and their derived natural products, as well as exploring the mechanisms by which these natural products act on NSCLC-particularly focusing on their applications-can provide valuable insights for the development of therapeutic drugs targeting NSCLC.

METHODS

A comprehensive, computerized literature search was conducted in PubMed, Embase, Web of Science, Cochrane Library, CNKI Scholar, the American Chemical Abstracts, and Wanfang Database up to June 2024, using the following keywords: "traditional Chinese medicine", "herbal medicine", "medicinal plants", and "herbal", paired with terms such as "non-small cell lung cancer", "therapy", "natural products", and "active ingredient".

RESULTS

Summarizing current research findings, we discovered eleven medicinal plants containing a total of fourteen natural products. Natural products have a significant impact on tumor progression in NSCLC, including apotosis, autophagy, pyrotosis, cell-cycle arrest and metasis. Moreover, natural products can modulate the activities of various immune cells and reshape the immune microenvironment. Combined with conventional cancer treatments, natural products demonstrate promising therapeutic effects and effectively reverse drug resistance. Furthermore,the use of nano-drug delivery systems to address limitations associated with natural products.

CONCLUSIONS

This review summarizes eleven medicinal plants containing a total of fourteen natural products that can enhance NSCLC treatment and indicates their action mechanisms. Furthermore, we also discuss limitations of natural products and explore the use of nano-drug delivery systems to address limitations associated with natural products.

Nobiletin ameliorates hormone-induced osteoblast apoptosis by modulating JAK2/STAT3 signaling

Our paper aimed to disclose the effects of nobiletin (NOB) on hormone-induced osteoblast apoptosis and potential action mechanism. MC3T3-E1 cells were randomly separated into normal group, glucocorticoid (GC) group, L-NOB group, M-NOB group, H-NOB group, and Colivelin group (Colivelin: JAK2/STAT3 activator). CCK-8 was applied to ascertain the activity of MC3T3-E1 cells. FITC-Annexin V/PI method was applied to measure cell apoptosis. Alkaline phosphatase (ALP) assay kit was applied to measure ALP activity. Enzyme linked immunosorbent assay (ELISA) was implemented to ascertain the levels of IL-6, IL-1β, TNF-α, and ROS. Western blotting was implemented to distinguish the expressions of JAK2/STAT3 pathway proteins. The viability of MC3T3-E1 cells, ALP activities, and bcl-2 protein level were considerably decreased, while the apoptotic rate, the levels of TNF-α, IL-1β, IL-6, ROS, and the expressions of pJAK2/JAK2, pSTAT3/STAT3, Caspase-3, and bax proteins were greatly increased in each group after GC treatment. In comparison with GC group, MC3T3-E1 cell viability, ALP activity, and bcl-2 protein level in the L-NOB group, M-NOB group, and H-NOB group were greatly increased. Conversely, the apoptotic rate, the levels of TNF-α, IL-1β, IL-6, ROS, and the expressions of pJAK2/JAK2, pSTAT3/STAT3, Caspase-3, and bax proteins were markedly reduced. In contrast to H-NOB group, the apoptotic rate, the levels of TNF-α, IL-1β, IL-6, ROS, and the expressions of pJAK2/JAK2, pSTAT3/STAT3, Caspase-3, and bax proteins in Colivelin group were considerably enhanced, while MC3T3-E1 cell viability, ALP activity, and bcl-2 protein level were greatly declined. NOB ameliorates hormone-induced osteoblast apoptosis by reducing JAK2/STAT3 signaling activity.

Targeting Programmed Cell Death in Acquired Sensorineural Hearing Loss: Ferroptosis, Necroptosis, and Pyroptosis

Sensorineural hearing loss (SNHL), the most commonly-occurring form of hearing loss, is caused mainly by injury to or the loss of hair cells and spiral ganglion neurons in the cochlea. Numerous environmental and physiological factors have been shown to cause acquired SNHL, such as ototoxic drugs, noise exposure, aging, infections, and diseases. Several programmed cell death (PCD) pathways have been reported to be involved in SNHL, especially some novel PCD pathways that have only recently been reported, such as ferroptosis, necroptosis, and pyroptosis. Here we summarize these PCD pathways and their roles and mechanisms in SNHL, aiming to provide new insights and potential therapeutic strategies for SNHL by targeting these PCD pathways.

Ocifisertib alleviates the gasdermin D-independent pyroptosis of nucleus pulposus cells by targeting GSDME

This study aimed to elucidate the cellular and molecular mechanisms of GSDME in GSDMD independent nucleus pulposus (NP) cell pyroptosis. We analyzed microarray datasets to identify differentially expressed genes (DEGs) in the progression of intervertebral disc degeneration (IDD) and conducted Gene Ontology analysis to elucidate DEGs-participated biological processes. We utilized lipopolysaccharides (LPS) to treat human primary NP cells to establish pyroptosis cell model. And siRNA was used to simulate a GSDMD-deficient environment. We used several regulators to figure out how GSDME was participate in pyroptosis via a GSDMD independent pathway. The molecular docking was conducted to identify compound that could possibly bind to GSDME and suppress its cleavage. Finally, Ocifisertib was intraperitoneally administered into IDD rat model to explore its therapeutic potential. Pyroptosis was activated in IDD. In vitro, LPS induced NP cell pyroptosis by promoting the cleavage of GSDMD and GSDME. In the absence of GSDMD, the cleavage of GSDME compensatively upregulated to mediate pyroptosis. Ocifisertib alleviated pyroptosis-mediated IDD by inhibiting GSDME cleavage in annulus fibrosus puncture-induced IDD rat model. Our study provides evidence that the cleavage of GSDME aggravates IDD by accelerating NP cell pyroptosis and demonstrates that Ocifisertib has therapeutic potential in IDD treatment.

Apoptotic Caspases-3 and -7 Cleave Extracellular Domains of Membrane-Bound Proteins from MDA-MB-231 Breast Cancer Cells

Apoptotic executioner caspases-3 and -7 are the main proteases responsible for the execution of apoptosis. Apoptosis is the main form of programmed cell death involved in organism development and maintenance of homeostasis and is commonly impaired in various pathologies. Predominately an immunologically silent form of cell death, it can become immunogenic upon loss of membrane integrity during progression to secondary necrosis, which mostly occurs when apoptotic bodies are not efficiently cleared by efferocytosis. In cancer, the efferocytic capacity can be overwhelmed following chemotherapeutic treatment, thereby providing an opportunity for the potential extracellular functions of executioner apoptotic caspases in the tumor microenvironment. By triggering apoptosis in Jurkat E6.1 acute T cell leukemia cells, we demonstrated that during progression to secondary necrosis, executioner caspases-3 and -7 can be found in the extracellular space. Furthermore, we showed that extracellularly active caspases-3 and -7 can cleave extracellular domains of membrane-bound proteins from MDA-MB-231 breast cancer cells, a function generally executed in the tumor microenvironment by several extracellular proteases from metalloprotease and cathepsin families. As such, this study provides the evidence for the potential involvement of apoptotic caspases-3 and -7 in extracellular proteolytic networks. Presented mass spectrometry data are available via ProteomeXchange with identifier PXD061399.

Controlling pyroptosis through post-translational modifications of gasdermin D

Pyroptosis, a lytic and programmed cell death pathway, is mediated by gasdermins (GSDMs), with GSDMD playing an important role in innate immunity and pathology. Upon activation, GSDMD is cleaved to release the active N-terminal fragment that oligomerizes into membrane pores, which promote pyroptosis and cytokine secretion, leading to inflammation. Emerging evidence indicates that post-translational modification (PTM) is an important regulatory mechanism of GSDMD activity. This review explores how PTMs, aside from proteolytic cleavage, control GSDMD activity and link biological contexts to pyroptosis in innate immunity and inflammation, which could inform future studies and therapeutic solutions for treating inflammatory conditions.

Inhibition of Caspase-1 Suppresses GSDMD-mediated Peritoneal Mesothelial Cell Pyroptosis and Inflammation in Peritoneal Fibrosis

Pyroptosis, belonging to programmed cell death, is shown to be mediated by gasdermin D (GSDMD) and gains more and more attention in innate immunity and multiple diseases. However, the role of GSDMD-mediated pyroptosis in peritoneal fibrosis (PF) remains unclear. This study observed NLRP3 inflammasome activation and pyroptosis in the peritoneum of long-term peritoneal dialysis (PD) patients with PF. Moreover, it is found that high glucose (HG) can induce the activation of NLRP3 inflammasome by regulating TLR4/NF-κB and JNK/p38 MAPK signaling in human peritoneal mesothelial cells (HPMCs), leading to subsequent Caspase-1 activation. The cleaved Caspase-1 promoted pyroptosis-related transmembrane pore formation through activating GSDMD-N, and stimulated the HPMCs to secrete inflammatory factors including IL-1β and IL-18. GSDMD global deletion or pharmacologic pretreatment with Caspase-1 specific inhibitor VX-765 effectively inhibited the pyroptosis and inflammation, thereby ameliorating PF. Additionally, treatment with VX-765 and transfected with Caspase-1 siRNA or GSDMD siRNA also inhibited the transmembrane pore formation and inflammatory factors secretion in HG-induced HPMCs. Consistent with these results, delayed treatment with VX-765 also alleviated PF, indicating the therapeutic effect of VX-765. Taken together, the results demonstrate that pyroptosis may be a novel therapeutic target for peritoneal fibrosis.

MOMP: A critical event in cell death regulation and anticancer treatment

Mitochondrial outer membrane permeabilization (MOMP) refers to the increase in permeability of the mitochondrial outer membrane, allowing proteins, DNA, and other molecules to pass through the intermembrane space into the cytosol. As a crucial event in the induction of apoptosis, MOMP plays a significant role in regulating various forms of cell death, including apoptosis, ferroptosis, and pyroptosis. Importantly, MOMP is not a binary process of "all-or-nothing." Under sub-lethal stress stimuli, cells may experience a phenomenon referred to as minority MOMP (miMOMP), where only a subset of mitochondria undergo functional impairment, thereby disrupting the normal life cycle of the cell. This can lead to pathological and physiological changes such as tumor formation, cellular senescence, innate immune dysfunction, and chronic inflammation. This review focuses on the diversity of MOMP events to elucidate how varying degrees of MOMP under different stress conditions influence cell fate. Additionally, it summarizes the current research progress on novel antitumor therapeutic strategies targeting MOMP in clinical contexts.

Shikonin Derivative Suppresses Colorectal Cancer Cells Growth via Reactive Oxygen Species-Mediated Mitochondrial Apoptosis and PI3K/AKT Pathway

Colorectal cancer (CRC) is one of the deadliest cancers globally, ranking as the third most prevalent and second most lethal malignancy worldwide. The standard treatment for CRC typically involves a combination of surgery, radiotherapy, and chemotherapy. Despite advancements in CRC treatment, the prognosis remains unsatisfactory, primarily due to unclear mechanisms underlying tumorigenesis and the aggression of CRC. The aberrant activation of the PI3K/AKT pathway is frequently implicated in the initiation, progression, and metastasis of CRC. Studies have demonstrated that shikonin (SK) exerts anti-cancer effects. In this study, we evaluated the anti-tumor activities of a series of semi-synthesized SK derivatives against CRC cells. Our findings revealed that the SK derivative (M12) significantly inhibited the proliferation and colony formation of CRC cells, reduced cell migration, and induced apoptosis. Mechanistically, M12 enhanced the production of reactive oxygen species and downregulated the mitochondrial membrane potential, ultimately leading to mitochondrial apoptosis. Furthermore, M12 exhibited anti-CRC effects by modulating the PI3K/AKT signaling pathway and significantly suppressed tumorigenicity without causing notable adverse effects in mice. Therefore, targeting the PI3K/AKT pathway could be a promising treatment for CRC. M12 appears to be a promising candidate for the effective and safe treatment of CRC.

Progesterone Enhances Sensitivity of Ovarian Cancer Cells to SN38 Through Inhibition of Topoisomerase I and Inducing Ferroptosis

BACKGROUND

Progesterone rapidly induces ovarian cancer cell death through non-genomic actions mediated by the membrane progesterone receptor (mPR).

AIMS

We investigated the combined effects of progesterone and SN38, an active metabolite of irinotecan, on ovarian cancer cells.

METHODS AND RESULTS

mPR-positive and PR-negative ovarian cancer cell lines were utilized in experiments. Tumor cells were exposed to SN38 or cisplatin for 48 h following exposure to progesterone for 30 min. The viable cell counts were measured using a colorimetric assay and the expression of topoisomerase I (TOPO-I), the direct target of SN38, was observed with or without exposure to progesterone. Moreover, we investigated the relationship between several types of programmed cell death and the SN38 sensitivity enhancement effect of progesterone using specific cell death inhibitors. The chemosensitivity to SN38 was 8.7- to 26.0-fold higher with the administration of progesterone than that without (p < 0.01), but not to cisplatin in ovarian cancer cells. Progesterone suppressed the expression of TOPO-I mRNA by less than 50% (p < 0.01). Furthermore, among various programmed cell death inhibitors, only the ferroptosis inhibitor attenuated the progesterone-induced SN38 chemosensitivity enhancement effect.

CONCLUSIONS

Progesterone increased sensitivity to SN38 by suppressing TOPO-I expression and inducing ferroptosis. The combination of progesterone and irinotecan could be a novel treatment modality for ovarian cancer.

The novel BCL-2/BCL-XL inhibitor APG-1252-mediated cleavage of GSDME enhances the antitumor efficacy of HER2-targeted therapy in HER2-positive gastric cancer

HER2-positive gastric cancer has a poor prognosis, with a high incidence of drug resistance and a lack of effective treatments for drug-resistant patients. The exploration of the mechanism of resistance to HER2-targeted therapy in HER2-positive gastric cancer and the identification of effective strategies to reverse it are urgently needed. In this study, we found that HER2-targeted agents upregulated the expression of GSDME and that the overexpression of GSDME attenuated the sensitivity of HER2-targeted agents. Furthermore, we observed that the BCL-2/BCL-XL inhibitor APG-1252 plus lapatinib promoted GSDME-mediated pyroptosis and exhibited remarkable antitumor activity both in vitro and in vivo. Mechanistically, APG-1252 combined with lapatinib synergistically induced GSDME-mediated pyroptosis in HER2-positive gastric cancer by activating caspase-dependent pathways and blocking the phospho-AKT/GSK-3β/MCL-1 signaling pathway. Our data indicated that the combination of lapatinib and APG-1252 had a synergistic antitumor effect on HER2-positive gastric cancer through the induction of caspase-3/GSDME-mediated apoptosis and pyroptosis.

Mechanistic insights into gasdermin-mediated pyroptosis

Pyroptosis, a novel mode of inflammatory cell death, is executed by membrane pore-forming gasdermin (GSDM) family members in response to extracellular or intracellular injury cues and is characterized by a ballooning cell morphology, plasma membrane rupture and the release of inflammatory mediators such as interleukin-1β (IL-1β), IL-18 and high mobility group protein B1 (HMGB1). It is a key effector mechanism for host immune defence and surveillance against invading pathogens and aberrant cancerous cells, and contributes to the onset and pathogenesis of inflammatory and autoimmune diseases. Manipulating the pore-forming activity of GSDMs and pyroptosis could lead to novel therapeutic strategies. In this Review, we discuss the current knowledge regarding how GSDM-mediated pyroptosis is initiated, executed and regulated, its roles in physiological and pathological processes, and the crosstalk between different modes of programmed cell death. We also highlight the development of drugs that target pyroptotic pathways for disease treatment.

Methamphetamine and HIV-1 Tat Synergistically Induce Microglial Pyroptosis Via Activation of the AIM2 Inflammasome

OBJECTIVE

Human immunodeficiency virus (HIV)-infected individuals who abuse methamphetamine (METH) exhibit more severe neurotoxicity and cognitive impairment. Pyroptosis, a programmed cell death pathway mediated by the inflammasome, has been implicated in various neurological diseases. This study aimed to elucidate the role of the AIM2 inflammasome in METH- and HIV-1 Tat-induced pyroptosis in human brain tissue and in vitro models.

METHODS

Postmortem brain tissue from HIV-infected individuals with a history of METH abuse was analyzed for pyroptosis markers and AIM2 inflammasome components using immunohistochemistry, immunofluorescence, and Western blotting. BV2 microglial cells were lentivirally transduced to knockdown AIM2 expression. DNA damage was assessed using Western blotting and the comet assay. Expression of pyroptosis-related proteins was evaluated by electron microscopy, Western blotting, and immunofluorescence. Cell viability was measured using the CCK8 assay.

RESULTS

Elevated levels of pyroptosis markers and AIM2 inflammasome components were observed in brain tissue from HIV-infected METH users. METH and Tat synergistically induced pyroptosis in BV2 cells in a time- and concentration-dependent manner, accompanied by DNA damage and activation of the AIM2 inflammasome. Knockdown of AIM2 significantly reduced the expression of pyroptosis-related proteins.

CONCLUSION

METH and HIV-1 Tat proteins synergistically induce microglial pyroptosis by activating the AIM2 inflammasome through dsDNA damage. These findings suggest that targeting the AIM2 inflammasome may be a promising therapeutic strategy for HIV-associated neurocognitive disorder (HAND).

Promoting the transition from pyroptosis to apoptosis in endothelial cells: a novel approach to alleviate methylglyoxal-induced vascular damage

BACKGROUND

Methylglyoxal (MGO)-induced cell death in vascular endothelial cells (VECs) plays a critical role in the progression of diabetic vascular complications (DVCs). Previous studies have shown that MGO can induce inflammatory pyroptosis, leading to VEC damage. However, the underlying mechanism remains unclear, and effective interventions are yet to be developed.

METHODS

Human umbilical vein endothelial cells (HUVECs) were used for in vitro experiments. Cell death modes were assessed through morphological observations. Mechanistic investigations were performed using immunofluorescence, flow cytometry, Western blotting, and ELISA. Inhibitors and adenoviruses were employed to validate the mechanisms. Vascular organoids in conjunction with AngioTool plug-in assays were used to evaluate VEC damage and angiogenic capacity. Mouse blood pressure was measured using the tail-cuff method, and vascular morphology was examined through hematoxylin and eosin (H&E) staining as well as immunofluorescence staining. Data were analyzed using the GraphPad Prism software.

RESULTS

Our study revealed that MGO induces pyroptosis in VECs via the Caspase3/gasdermin E (GSDME) pathway. Furthermore, the saponin monomer 13 of dwarf lilyturf tuber (DT-13), inhibited MGO-induced pyroptosis and promoted the generation of apoptotic bodies, facilitating the transition from pyroptosis to apoptosis. Mechanistically, DT-13 suppressed the Caspase3-mediated cleavage of GSDME and non-muscle myosin heavy chain IIA (NMMHC IIA), while increasing the phosphorylation of myosin light chain 2 (MLC2), which facilitated apoptotic body formation. Additionally, DT-13 was shown to mitigate VEC damage, inhibit angiogenesis, reduce vascular remodeling, and alleviate MGO-induced hypertension.

CONCLUSIONS

This study uncovers a novel mechanism through which MGO induces VEC damage, highlighting the therapeutic significance of the transition from pyroptosis to apoptosis in this process. These findings suggest potential therapeutic strategies for managing diabetic angiopathy. Furthermore, DT-13 emerges as a promising compound for therapeutic intervention, offering new possibilities for clinical applications.

The EMCV protein 2B* is required for efficient cell lysis via both caspase-3-dependent and -independent pathways during infection

2B* is a poorly characterized protein encoded by an overlapping ORF in the genome of encephalomyocarditis virus (EMCV). We have previously found 2B* to have a role in innate immune antagonism; however, this role is distinct from an earlier described phenotype whereby 2B*KO viruses exhibit extremely small plaques compared to WT. Here, we report that the small plaque phenotype is recapitulated by novel EMCV mutant viruses harbouring mutations across the C-terminal domain of 2B*, confirming a functional role of 2B* in promoting viral spread. We found that 2B*KO EMCV displays impaired extracellular virus titres compared to WT EMCV, despite producing a similar number of infectious particles overall. This correlates with a reduction in cell lysis and lower levels of caspase-3 cleavage occurring during infection. Further investigation using caspase inhibitors and knockout cells revealed that WT EMCV can utilize both caspase-3-dependent and caspase-3-independent pathways to achieve cell lysis, the former of which is likely to be GSDME-mediated pyroptosis. 2B* increases the efficiency of both lytic pathways through an as-yet-undefined mechanism. This work reveals 2B*, a protein only found in EMCV, to be a key regulator of multiple lytic cell death pathways, leading to enhanced rates of virus release. This explains the rapid cell death observed during WT EMCV infection and the small plaque phenotype seen in both 2B*KO and previously described 2B* mutant viruses.

Endoplasmic reticulum membrane remodeling by targeting reticulon-4 induces pyroptosis to facilitate antitumor immune

Pyroptosis is an identified programmed cell death that has been highly linked to endoplasmic reticulum (ER) dynamics. However, the crucial proteins for modulating dynamic ER membrane curvature change that trigger pyroptosis are currently not well understood. In this study, a biotin-labeled chemical probe of potent pyroptosis inducer α-mangostin (α-MG) was synthesized. Through protein microarray analysis, reticulon-4 (RTN4/Nogo), a crucial regulator of ER membrane curvature, was identified as a target of α-MG. We observed that chemically induced proteasome degradation of RTN4 by α-MG through recruiting E3 ligase UBR5 significantly enhances the pyroptosis phenotype in cancer cells. Interestingly, the downregulation of RTN4 expression significantly facilitated a dynamic remodeling of ER membrane curvature through a transition from tubules to sheets, consequently leading to rapid fusion of the ER with the cell plasma membrane. In particular, the ER-to-plasma membrane fusion process is supported by the observed translocation of several crucial ER markers to the "bubble" structures of pyroptotic cells. Furthermore, α-MG-induced RTN4 knockdown leads to pyruvate kinase M2 (PKM2)-dependent conventional caspase-3/gasdermin E (GSDME) cleavages for pyroptosis progression. In vivo, we observed that chemical or genetic RTN4 knockdown significantly inhibited cancer cells growth, which further exhibited an antitumor immune response with anti-programmed death-1 (anti-PD-1). In translational research, RTN4 high expression was closely correlated with the tumor metastasis and death of patients. Taken together, RTN4 plays a fundamental role in inducing pyroptosis through the modulation of ER membrane curvature remodeling, thus representing a prospective druggable target for anticancer immunotherapy.

Berberine shaping the tumor immune landscape via pyroptosis

Pyroptosis is a programmed cell death (PCD) mainly mediated by the Gasdermin family of proteins, among which Gasdermin E (GSDME) is considered a tumor suppressor gene. GSDME can recruit immune cells to the tumor microenvironment (TME) and promote their effects. Activating and enhancing adaptive immunity through GSDME is a potential solution for anti-tumor therapy. Here we reported that berberine (BBR), a small molecule from traditional Chinese medicine, as a GSDME activator, induced caspase-3 (C-3)/GSDME pathway-mediated pyroptosis through the mitochondrial pathway, improved the immunosuppressive state of the tumor microenvironment, and thus promoted anti-tumor immunity. We determined the induction of pyroptosis of 4 T1 cells by BBR through various experiments, and investigated the immune activation effect of BBR by co-culture in vitro, which induced DCs maturation and macrophage polarization. Zebrafish embryo toxicity experiments were used to evaluate the in vivo safety of berberine. Furthermore, the in vivo antitumor and immune activation effects of BBR were investigated using 4 T1 orthotopic model mice, and the results showed that BBR could eliminate orthotopic tumor cells by activating local and systemic immunity. Moreover, we observed that BBR significantly inhibited breast cancer lung metastasis. In summary, our results showd the role of BBR as a GSDME activator stimulated both local and systemic antitumor immune responses by inducing pyroptosis, effectively preventing tumor development and metastasis.

Hypericin photoactivation induces triple-negative breast cancer cells pyroptosis by targeting the ROS/CALR/Caspase-3/GSDME pathway

INTRODUCTION

Hypericin (HP), a natural photosensitizer, has demonstrated great efficacy in photodynamic therapy (PDT) for cancer treatment. In addition to the induction of apoptosis and necrosis through reactive oxygen species (ROS) generation, the therapeutic mechanisms and targets of PDT-HP remain unknown.

OBJECTIVES

To investigate the direct targets and mechanisms of action of photoactivated hypericin in the inhibition of triple-negative breast cancer (TNBC).

METHODS

Cell pyroptosis was examined via LDH release, SYTOX Green staining, and ELISA. RNA sequencing, network pharmacology, drug affinity target stability (DARTS)-tandem mass spectrometry (MS/MS), and molecular docking were employed to identify drug targets. Furthermore, immunoblotting and flow cytometry were utilized to elucidate the mechanisms of drug action.

RESULTS

Our research revealed that PDT-HP can induce pyroptosis in TNBC cells. Further investigation revealed that PDT-HP induces endoplasmic reticulum stress, activating Caspase-3 and gasdermin E (GSDME) to trigger TNBC cell pyroptosis. RNA-seq, network pharmacology, and DARTS-MS/MS proteomic analyses revealed that the endoplasmic reticulum protein calreticulin (CALR) is a potential HP target and that interfering with CALR inhibited PDT-HP-induced pyroptosis. During PDT-HP treatment, the interaction between CALR and SERCA2 inactivates SERCA2, increasing the susceptibility of cells to increased intracellular Ca2+ levels under oxidative stress. This triggered endoplasmic reticulum stress and activated Caspase3, which further cleaved GSDME, releasing GSDME-N and ultimately leading to pyroptosis in TNBC cells.

CONCLUSION

In this study, we provide insight into the antitumor mechanism by examining the pharmacological mechanism by which PDT-HP regulates TNBC cell pyroptosis via the ROS/CALR/Caspase-3/GSDME signaling axis.

ZDHHC2 promoted antimycobacterial responses by selective autophagic degradation of B-RAF and C-RAF in macrophages

S-Palmitoylation is a reversible post-translational modification involving saturated fatty acid palmitate-to-cysteine linkage in the protein, which guides many aspects of macrophage physiology in health and disease. However, the precise role and underlying mechanisms of palmitoylation in Mycobacterium tuberculosis infection of macrophages remain elusive. Here, we found that M. tuberculosis infection induced the expression of zinc-finger DHHC domain-type palmitoyl-transferases (ZDHHCs), particularly ZDHHC2, in mouse macrophages. Furthermore, ZDHHC2 deficiency in mouse macrophages impaired the immunity against M. tuberculosis and reduced the production of various proinflammatory cytokines. Mechanistic studies revealed the involvement of ZDHHC2 in mediating the palmitoylation of B-RAF and C-RAF, affecting their autophagic degradation and stabilizing protein levels. The increased abundance of B-RAF and C-RAF subsequently increases the activity of the extracellular signal-regulated kinase (ERK) signaling pathway, affecting the survival of M. tuberculosis within macrophages. These findings suggest that ZDHHC2 is a potential target for treating tuberculosis.

Ferroptosis and pyroptosis are connected through autophagy: a new perspective of overcoming drug resistance

Drug resistance is a common challenge in clinical tumor treatment. A reduction in drug sensitivity of tumor cells is often accompanied by an increase in autophagy levels, leading to autophagy-related resistance. The effectiveness of combining chemotherapy drugs with autophagy inducers/inhibitors has been widely confirmed, but the mechanisms are still unclear. Ferroptosis and pyroptosis can be affected by various types of autophagy. Therefore, ferroptosis and pyroptosis have crosstalk via autophagy, potentially leading to a switch in cell death types under certain conditions. As two forms of inflammatory programmed cell death, ferroptosis and pyroptosis have different effects on inflammation, and the cGAS-STING signaling pathway is also involved. Therefore, it also plays an important role in the progression of some chronic inflammatory diseases. This review discusses the relationship between autophagy, ferroptosis and pyroptosis, and attempts to uncover the reasons behind the evasion of tumor cell death and the nature of drug resistance.

New insights into constitutive neutrophil death

Neutrophils undergo rapid aging and death known as constitutive or spontaneous death. Constitutive neutrophil death (CND) contributes to neutrophil homeostasis and inflammation resolution. CND has long been considered to be apoptotic until our findings reveal that it was a heterogeneous combination of diverse death. Furthermore, dead neutrophils retain functional roles via multiple manners. This review provides an overview of current research on the mechanism and modulation of CND. More noteworthy, we also summarize the after-death events of neutrophils. The fate of neutrophils can be changed under pathological conditions, so the involvement of CND in diseases and CND-related therapeutic strategies are also addressed.

Paris saponin VII induces Caspase-3/GSDME-dependent pyroptosis in pancreatic ductal adenocarcinoma cells by activating ROS/Bax signaling

Objective

Paridis Rhizoma (Chonglou in Chinese), a traditional Chinese herbal medicine, has been shown have strong anti-tumor effects. Paris saponin VII (PSVII), an active constituent isolated from Paridis Rhizoma, was demonstrated to significantly suppress the proliferation of BxPC-3 cells in our previous study. Here, we aimed to elucidate the anti-pancreatic ductal adenocarcinoma (PDAC) effect of PSVII and the underlying mechanism.

Methods

Cell viability was determined by CCK-8, colony formation, and cell migration assays. Cell apoptosis and reactive oxygen species (ROS) production were measured by flow cytometry with annexin V/propidine iodide (Annexin V/PI) and 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA), respectively. Pyroptosis was evaluated by morphological features, Hoechst 33342/PI staining assay, and release of lactate dehydrogenase (LDH). JC-1 fluorescent dye was employed to measure mitochondrial membrane potential. Western blotting and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) were used to determine the levels of proteins or mRNAs. The effect in vivo was assessed by a xenograft tumor model.

Results

PSVII inhibited the viability of PDAC cells (BxPC-3, PANC-1, and Capan-2 cells) and induced gasdermin E (GSDME) cleavage, as well as the simultaneous cleavage of Caspase-3 and poly (ADP-ribose) polymerase 1 (PARP). Knockdown of GSDME shifted PSVII-induced pyroptosis to apoptosis. Additionally, the effect of PSVII was significantly attenuated by Z-Asp(OMe)-Glu(OMe)-Val-Asp(OMe)-fluoromethylketone (Z-DEVD-FMK), on the induction of GSDME-dependent pyroptosis. PSVII also elevated intracellular ROS accumulation and stimulated Bax and Caspase-3/GSDME to conduct pyroptosis in PDAC cells. The ROS scavenger N-acetyl cysteine (NAC) suppressed the release of LDH and inhibited Caspase-9, Caspase-3, and GSDME cleavage in PDAC cells, ultimately reversing PSVII-induced pyroptosis. Furthermore, in a xenograft tumor model, PSVII markedly suppressed the growth of PDAC tumors and induced pyroptosis.

Conclusion

These results demonstrated that PSVII exerts therapeutic effects through Caspase-3/GSDME-dependent pyroptosis and may constitute a novel strategy for preventing chemotherapeutic resistance in patients with PDAC in the future.

USP11 promotes renal tubular cell pyroptosis and fibrosis in UUO mice via inhibiting KLF4 ubiquitin degradation

The pyroptosis of renal tubular epithelial cells leads to tubular loss and inflammation and then promotes renal fibrosis. The transcription factor Krüppel-like factor 4 (KLF4) can bidirectionally regulate the transcription of target genes. Our previous study revealed that sustained elevation of KLF4 is responsible for the transition of acute kidney injury (AKI) into chronic kidney disease (CKD) and renal fibrosis. In this study, we explored the upstream mechanisms of renal tubular epithelial cell pyroptosis from the perspective of posttranslational regulation and focused on the transcription factor KLF4. Mice were subjected to unilateral ureteral obstruction (UUO) surgery and euthanized on D7 or D14 for renal tissue harvesting. We showed that the pyroptosis of renal tubular epithelial cells mediated by both the Caspase-1/GSDMD and Caspase-3/GSDME pathways was time-dependently increased in UUO mouse kidneys. Furthermore, we found that the expression of the transcription factor KLF4 was also upregulated in a time-dependent manner in UUO mouse kidneys. Tubular epithelial cell-specific Klf4 knockout alleviated UUO-induced pyroptosis and renal fibrosis. In Ang II-treated mouse renal proximal tubular epithelial cells (MTECs), we demonstrated that KLF4 bound to the promoter regions of Caspase-3 and Caspase-1 and directly increased their transcription. In addition, we found that ubiquitin-specific protease 11 (USP11) was increased in UUO mouse kidneys. USP11 deubiquitinated KLF4. Knockout of Usp11 or pretreatment with the USP11 inhibitor mitoxantrone (3 mg/kg, i.p., twice a week for two weeks before UUO surgery) significantly alleviated the increases in KLF4 expression, pyroptosis and renal fibrosis. These results demonstrated that the increased expression of USP11 in renal tubular cells prevents the ubiquitin degradation of KLF4 and that elevated KLF4 promotes inflammation and renal fibrosis by initiating tubular cell pyroptosis.

Pyropheophorbide-α methyl ester-mediated photodynamic therapy triggers pyroptosis in osteosarcoma cells via the ROS/caspase-3/GSDME pathway

BACKGROUND

Pyropheophorbide-α methyl ester-mediated photodynamic therapy(MPPa-PDT) is a candidate treatment for solid tumors, including osteosarcoma. Pyroptosis has garnered significant attention in cancer research due to its pro-inflammatory and immunomodulatory nature. This study investigated the mechanism and role of MPPa-PDT-induced pyroptosis in osteosarcoma cells.

METHODS

We treated human osteosarcoma 143b and HOS cells with MPPa at concentrations of 0.5 μM and 0.25 μM, respectively, then irradiated the cells with LED light at 630 nm wavelength with an energy density of 4.8 J/cm2. Cell viability and apoptosis ratio were detected using CCK-8 and Annexin V-Propidium Iodide staining, respectively. Intracellular reactive oxygen species (ROS) levels and mitochondrial membrane potential (MtΔψ) were assessed using 2',7'-Dichlorofluorescin diacetate, and JC-1 staining kits, respectively. Scanning Electron Microscopy (SEM) was utilized to examine cell ultrastructure. The morphological changes of the cells were observed by an inverted microscope. Western blotting analysis was conducted to measure protein levels. To elucidate the mechanism and role, we re-evaluated relevant parameters after pretreating with NAC,Si caspase-3, and Si GSDME.

RESULTS

MPPa-PDT inhibited the activity of osteosarcoma 143b and HOS cells and induced pyroptosis with mitochondrial damage, ROS aggregation, and activation of Caspase-3 and GSDME. The effects of MPPa-PDT on the activity and apoptosis of osteosarcoma cells were partially reversed after pretreating with Si GSDME. After NAC pretreatment, the activation of pyroptosis and Caspase-3 induced by MPPa-PDT was partially reversed. After Si Caspase-3 pretreatment, the pyroptosis induced by MPPa-PDT was partially reversed.

CONCLUSION

MPPa-PDT can induce pyroptosis in osteosarcoma cells, which has the effect of enhancing apoptotic processes. Mitochondrial damage and ROS/caspase-3/GSDME pathway are the possible mechanisms of pyroptosis induced by MPPa-PDT.

Eradication of Large Tumors by Nanoscale Drug Self-Assembly

Most patients with cancer are first diagnosed at an advanced disease stage, when tumors are already large and/or metastases are present. This circumstance has a negative impact on the prognosis and therapeutic effect of anticancer drugs. In this study, it is demonstrated that photosensitizer chlorin e6 and the photochemotherapy drug mitoxantrone self-assemble into relatively stable nanoassemblies (CM NAs) through hydrogen-bonding effect, π-π stacking, and hydrophobic interactions. Administration of CM NAs in combination with 660 nm laser irradiation shows chemotherapeutic, photothermal, and photodynamic effects, causing tumor cell apoptosis and pyroptosis and enabling noninvasive tumor ablation without compromising the surrounding normal tissue. More importantly, treatment with CM NAs increases tumor immunogenicity, leading to a strong and long-term antitumor immune response that eradicates large tumors and provides long-term protection against tumor recurrence on various tumor models.

Crosstalk of pyroptosis and cytokine in the tumor microenvironment: from mechanisms to clinical implication

In the realm of cancer research, the tumor microenvironment (TME) plays a crucial role in tumor initiation and progression, shaped by complex interactions between cancer cells and surrounding non-cancerous cells. Cytokines, as essential immunomodulatory agents, are secreted by various cellular constituents within the TME, including immune cells, cancer-associated fibroblasts, and cancer cells themselves. These cytokines facilitate intricate communication networks that significantly influence tumor initiation, progression, metastasis, and immune suppression. Pyroptosis contributes to TME remodeling by promoting the release of pro-inflammatory cytokines and sustaining chronic inflammation, impacting processes such as immune escape and angiogenesis. However, challenges remain due to the complex interplay among cytokines, pyroptosis, and the TME, along with the dual effects of pyroptosis on cancer progression and therapy-related complications like cytokine release syndrome. Unraveling these complexities could facilitate strategies that balance inflammatory responses while minimizing tissue damage during therapy. This review delves into the complex crosstalk between cytokines, pyroptosis, and the TME, elucidating their contribution to tumor progression and metastasis. By synthesizing emerging therapeutic targets and innovative technologies concerning TME, this review aims to provide novel insights that could enhance treatment outcomes for cancer patients.

Mechanisms and cross-talk of regulated cell death and their epigenetic modifications in tumor progression

Cell death is a fundamental part of life for metazoans. To maintain the balance between cell proliferation and metabolism of human bodies, a certain number of cells need to be removed regularly. Hence, the mechanisms of cell death have been preserved during the evolution of multicellular organisms. Tumorigenesis is closely related with exceptional inhibition of cell death. Mutations or defects in cell death-related genes block the elimination of abnormal cells and enhance the resistance of malignant cells to chemotherapy. Therefore, the investigation of cell death mechanisms enables the development of drugs that directly induce tumor cell death. In the guidelines updated by the Cell Death Nomenclature Committee (NCCD) in 2018, cell death was classified into 12 types according to morphological, biochemical and functional classification, including intrinsic apoptosis, extrinsic apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, pyroptosis, PARP-1 parthanatos, entotic cell death, NETotic cell death, lysosome-dependent cell death, autophagy-dependent cell death, immunogenic cell death, cellular senescence and mitotic catastrophe. The mechanistic relationships between epigenetic controls and cell death in cancer progression were previously unclear. In this review, we will summarize the mechanisms of cell death pathways and corresponding epigenetic regulations. Also, we will explore the extensive interactions between these pathways and discuss the mechanisms of cell death in epigenetics which bring benefits to tumor therapy.

CAR-armored-cell therapy in solid tumor treatment

Over the past decade, chimeric antigen receptor (CAR)-T cell therapy has emerged as a revolutionary immunotherapeutic approach to combat cancer. This therapy constructs a CAR on the surface of T cells through genetic engineering techniques. The CAR is formed from a combination of antibody-derived or ligand-derived domains and T-cell receptor (TCR) domains. This enables T cells to specifically bind to and activate against tumor cells. However, the efficacy of CAR-T cells in solid tumors remains inconclusive due to several challenges such as poor tumor trafficking, infiltration, and the immunosuppressive tumor microenvironment (TME). In response, CAR natural killer (CAR-NK) and CAR macrophages (CAR-M) have been developed as complementary strategies for solid tumors. CAR-NK cells do not require HLA compatibility, demonstrate reduced toxicity, and are thus seen as potential substitutes for CAR-T cells. Furthermore, CAR-M immunotherapy is also being researched and has shown phagocytic capabilities and tumor-antigen presentation. This study discusses the features, advantages, and limitations of CAR-T, CAR-NK, and CAR-M cells in the treatment of solid tumors and suggests prospective solutions for enhancing the efficacy of CAR host-cell-based immunotherapy.

The role of pyroptosis in cancer: key components and therapeutic potential

Pyroptosis is a lytic and inflammatory form of gasdermin protein-mediated programmed cell death that is typically initiated by inflammasomes. The inflammasome response is an effective mechanism for eradicating germs and cancer cells in the event of cellular injury. The gasdermin family is responsible for initiating pyroptosis, a process in which holes are made in the cell membrane to allow inflammatory chemicals to escape. Mounting evidence indicates that pyroptosis is critical for controlling the development of cancer. In this review, we provide a general overview of pyroptosis, examine the relationship between the primary elements of pyroptosis and tumors, and stress the necessity of pyroptosis-targeted therapy in tumors. Furthermore, we explore its dual nature as a double-edged sword capable of both inhibiting and facilitating the growth of cancer, depending on the specific conditions. Ultimately, pyroptosis is a phenomenon that has both positive and negative effects on tumors. Using this dual impact in a reasonable manner may facilitate investigation into the initiation and progression of tumors and offer insights for the development of novel treatments centered on pyroptosis.

Emerging roles of palmitoylation in pyroptosis

Pyroptosis is a lytic, proinflammatory type of programmed cell death crucial for the immune response to pathogen infections and internal danger signals. Gasdermin D (GSDMD) acts as the pore-forming protein in pyroptosis following inflammasome activation. While recent research has improved our understanding of pyroptosis activation and execution, many aspects regarding the molecular mechanisms controlling inflammasome and GSDMD activation remain to be elucidated. A growing body of literature has shown that S-palmitoylation, a reversible post-translational modification (PTM) that attaches palmitate to cysteine residues, contributes to multi-layered regulation of pyroptosis. This review summarizes the emerging roles of S-palmitoylation in pyroptosis research with a focus on mechanisms that regulate NLRP3 inflammasome and GSDMD activation.

Pyroptosis induced by natural products and their derivatives for cancer therapy

Natural products, which are compounds extracted and/or refined from plants and microbes in nature, have great potential for the discovery of therapeutic agents, especially for infectious diseases and cancer. In recent years, natural products have been reported to induce multiple cell death pathways to exhibit antitumor effects. Among them, pyroptosis is a unique programmed cell death (PCD) characterized by continuous cell membrane permeability and intracellular content leakage. According to the canonical and noncanonical pathways, the formation of gasdermin-N pores involves a variety of transcriptional targets and post-translational modifications. Thus, tailored control of PCD may facilitate dying cells with sufficient immunogenicity to activate the immune system to eliminate other tumor cells. Therefore, we summarized the currently reported natural products or their derivatives and their nano-drugs that induce pyroptosis-related signaling pathways. We reviewed six main categories of bioactive compounds extracted from natural products, including flavonoids, terpenoids, polyphenols, quinones, artemisinins, and alkaloids. Correspondingly, the underlying mechanisms of how these compounds and their derivatives engage in pyroptosis are also discussed. Moreover, the synergistic effect of natural bioactive compounds with other antitumor therapies is proposed as a novel therapeutic strategy for traditional chemotherapy, radiotherapy, chemodynamic therapy, photodynamic therapy, photothermal therapy, hyperthermal therapy, and sonodynamic therapy. Consequently, we provide insights into natural products to develop a novel antitumor therapy or qualified adjuvant agents by inducing pyroptosis, which may eventually be applied clinically.

Paralichthys olivaceus GSDME-mediated pyroptosis is regulated by multiple caspases in different manners

Pyroptosis is a type of programmed cell death mediated by gasdermin (GSDM). GSDM is activated by caspase (CASP), which cleaves GSDM to release the N-terminal (NT) fragment that forms channels in the plasma membrane and leads to cell death. To date, research on pyroptosis in teleost is limited. In this study, we examined the activation and regulation mechanism of pyroptosis in flounder Paralichthys olivaceus. P. olivaceus gasdermin E (PoGSDME) was found to be cleaved by six P. olivaceus caspases (PoCASP1/3a/3b/7/8a/8b). PoCASP1/3a/3b/7 cleaved primarily at 245FEAD248, which generated an NT fragment (NT248) that induced robust pyroptosis. PoCASP8a/8b cleaved both the full length PoGSDME and NT248 at 202IEKD205, thus destroying the biological activity of PoGSDME and NT248. Nine residues crucial for PoGSDME function were identified, of which, F2, L19, and G85 were essential to plasma membrane translocation. During bacterial infection, PoGSDME and PoCASP1 expressions were significantly upregulated in flounder tissues, and PoGSDME, as well as PoCASP1, activation occurred in flounder cells accompanied with the processing cleavage of IL-1β and IL-18. Together these results revealed both the activation and the inhibition mechanisms of GSDME-mediated pyroptosis in flounder, and added new insights into the regulation of pyroptosis in fish.

The PINK1/Parkin signaling pathway-mediated mitophagy: a forgotten protagonist in myocardial ischemia/reperfusion injury

Myocardial ischemia causes extensive damage, further exacerbated by reperfusion, a phenomenon called myocardial ischemia/reperfusion injury (MIRI). Nowadays, the pathological mechanisms of MIRI have received extensive attention. Oxidative stress, multiple programmed cell deaths, inflammation and others are all essential pathological mechanisms contributing to MIRI. Mitochondria are the energy supply centers of cells. Numerous studies have found that abnormal mitochondrial function is an essential "culprit" of MIRI, and mitophagy mediated by the phosphatase and tensin homolog (PTEN)-induced kinase 1 (PINK1)/Parkin signaling pathway is an integral part of maintaining mitochondrial function. Therefore, exploring the association between the PINK1/Parkin signaling pathway-mediated mitophagy and MIRI is crucial. This review will mainly summarize the crucial role of the PINK1/Parkin signaling pathway-mediated mitophagy in MIR-induced several pathological mechanisms and various potential interventions that affect the PINK1/Parkin signaling pathway-mediated mitophagy, thus ameliorating MIRI.

The regulation of pyroptosis by post-translational modifications: molecular mechanisms and therapeutic targets

Pyroptosis, a type of programmed cell death mediated by gasdermin family proteins, releases a large amount of immune stimulatory substances, which further contribute to inflammation and elicit an adaptive immune response against tumours and pathogens. And it occurs through multiple pathways that involve the activation of specific caspases and the cleavage of gasdermins. Post-translational modifications (PTMs) could influence the chemical properties of the modified residues and neighbouring regions, ultimately affecting the activity, stability, and functions of proteins to regulate pyroptosis. Many studies have been conducted to explore the influence of PTMs on the regulation of pyroptosis. In this review, we provide a comprehensive summary of different types of PTMs that influence pyroptosis, along with their corresponding modifying enzymes. Moreover, it elaborates on the specific contributions of different PTMs to pyroptosis and delves into how the regulation of these modifications can be leveraged for therapeutic interventions in cancer and inflammatory diseases.

TNF-ɑ induces mitochondrial dysfunction to drive NLRP3/Caspase-1/GSDMD-mediated pyroptosis in MCF-7 cells

Pyroptosis is a gasdermin-mediated pro-inflammatory form of programmed cell death (PCD). Tumor necrosis factor-ɑ (TNF-ɑ) is an inflammatory cytokine, and some studies have shown that TNF-ɑ can cause pyroptosis of cells and exert anti-tumor effects. However, whether TNF-ɑ exerts anti-tumor effects on breast cancer cells by inducing pyroptosis has not been reported. In this study, to explore the impact of TNF-ɑ on pyroptosis in breast cancer cells, we treated MCF-7 cells with TNF-ɑ and found that TNF-ɑ induced cell death. Moreover, we observed that the dead cells were swollen with obvious balloon-like bubbles, which was a typical sign of pyroptosis. Further studies have found that the anti-tumor effect of TNF-ɑ on breast cancer cells in vitro was achieved through the canonical pyroptosis pathway. In addition, TNF-ɑ-induced pyroptosis in MCF-7 cells was associated with mitochondrial dysfunction, in which mitochondrial membrane potential was decreased and mitochondrial ROS production was increased. After inhibiting ROS production, the activation effect of TNF-ɑ on NLRP3/Caspase-1/GSDMD pathway was weakened, and the inhibitory effect of TNF-ɑ on the growth of MCF-7 cells in vitro was also decreased, further confirming the involvement of ROS in TNF-ɑ-induced pyroptosis. Overall, our study revealed a new mechanism by which TNF-ɑ exerts an anti-tumor effect by inducing pyroptosis in MCF-7 cells through the ROS/NLRP3/Caspase-1/GSDMD pathway, which may provide new therapeutic ideas for the treatment of breast cancer.

Fucoidan-derived carbon dots as nanopenetrants of blood-brain barrier for Parkinson's disease treatment

Parkinson's Disease (PD) stands as a prevalent neurodegenerative disorder. However, current pharmacotherapies for PD face challenges due to inadequate penetration through the blood-brain barrier (BBB), posing limitations on their therapeutic efficacy. Considering the potential of negatively charged carbon dots (CDs) in retaining functional groups from precursor molecules and vertically crossing the BBB, this study focuses on the utilization of fucoidan (FD), a promising pharmaceutical candidate with neuroprotective effects on dopamine-active neurons, for the development of negatively charged CDs through a one-step hydrothermal method, aiming to achieve efficient BBB penetration for PD treatment. The obtained fucoidan-derived carbon dots (FDCDs) exhibit the fundamental characteristics of CDs, such as nanostructure particles with an average diameter of less than 10 nm and significant photoluminescence ability. They also retain the abundant functional groups of SO42- from FD, resulting in a negatively charged surface. In vitro cell experiments were conducted to validate the ability of FDCDs to mitigate 1-Methyl-4-phenylpyridinium ion (MPP+)-induced damage in PC12 cells via anti-inflammatory pathway, antioxidant capacity, and anti-apoptotic effect. After confirming the ability of FDCDs to traverse the BBB using 3D small animal imaging, the intravenous administration of FDCDs via tail injection was observed to successfully restore the motor function in 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice. Notably, no apparent biotoxic response was observed, highlighting the promising potential of FDCDs for effective PD therapy.

Advancing Roles and Therapeutic Potentials of Pyroptosis in Host Immune Defenses against Tuberculosis

Tuberculosis (TB), an infectious disease caused by Mycobacterium tuberculosis (Mtb) infection, remains a deadly global public health burden. The use of recommended drug combinations in clinic has seen an increasing prevalence of drug-resistant TB, adding to the impediments to global control of TB. Therefore, control of TB and drug-resistant TB has become one of the most pressing issues in global public health, which urges the exploration of potential therapeutic targets in TB and drug-resistant TB. Pyroptosis, a form of programmed cell death characterized by cell swelling and rupture, release of cellular contents and inflammatory responses, has been found to promote pathogen clearance and adopt crucial roles in the control of bacterial infections. It has been demonstrated that Mtb can cause host cell pyroptosis, and these host cells, which are infected by Mtb, can kill Mtb accompanied by pyroptosis, while, at the same time, pyroptosis can also release intracellular Mtb, which may potentially worsen the infection by exacerbating the inflammation. Here, we describe the main pathways of pyroptosis during Mtb infection and summarize the identified effectors of Mtb that regulate pyroptosis to achieve immune evasion. Moreover, we also discuss the potentials of pyroptosis to serve as an anti-TB therapeutic target, with the aim of providing new ideas for the development of TB treatments.

Pyroptosis: Induction and inhibition strategies for immunotherapy of diseases

Cell death is a central process for organismal health. Pyroptosis, namely pyroptotic cell death, is recognized as a critical type that disrupts membrane and triggers pro-inflammatory cytokine secretion via gasdermins, providing a robust form of cytolysis. Meanwhile, along with the thorough research, a great deal of evidence has demonstrated the dual effects of pyroptosis in host defense and inflammatory diseases. More importantly, the recent identification of abundant gasdermin-like proteins in bacteria and fungi suggests an ancient origin of pyroptosis-based regulated cell death in the life evolution. In this review, we bring a general overview of pyroptosis pathways focusing on gasdermin structural biology, regulatory mechanisms, and recent progress in induction and inhibition strategies for disease treatment. We look forward to providing an insightful perspective for readers to comprehend the frame and challenges of the pyroptosis field, and to accelerating its clinical application.

Gasdermin D cysteine residues synergistically control its palmitoylation-mediated membrane targeting and assembly

Gasdermin D (GSDMD) executes the cell death program of pyroptosis by assembling into oligomers that permeabilize the plasma membrane. Here, by single-molecule imaging, we elucidate the yet unclear mechanism of Gasdermin D pore assembly and the role of cysteine residues in GSDMD oligomerization. We show that GSDMD preassembles at the membrane into dimeric and trimeric building blocks that can either be inserted into the membrane, or further assemble into higher-order oligomers prior to insertion into the membrane. The GSDMD residues Cys39, Cys57, and Cys192 are the only relevant cysteines involved in GSDMD oligomerization. S-palmitoylation of Cys192, combined with the presence of negatively-charged lipids, controls GSDMD membrane targeting. Simultaneous Cys39/57/192-to-alanine (Ala) mutations, but not Ala mutations of Cys192 or the Cys39/57 pair individually, completely abolish GSDMD insertion into artificial membranes as well as into the plasma membrane. Finally, either Cys192 or the Cys39/Cys57 pair are sufficient to enable formation of GSDMD dimers/trimers, but they are all required for functional higher-order oligomer formation. Overall, our study unveils a cooperative role of Cys192 palmitoylation-mediated membrane binding and Cys39/57/192-mediated oligomerization in GSDMD pore assembly. This study supports a model in which Gasdermin D oligomerization relies on a two-step mechanism mediated by specific cysteine residues.

Ubiquitin-independent degradation of Bim blocks macrophage pyroptosis in sepsis-related tissue injury

Pyroptosis, a typical inflammatory cell death mode, has been increasingly demonstrated to have therapeutic value in inflammatory diseases such as sepsis. However, the mechanisms and therapeutic targets of sepsis remain elusive. Here, we reported that REGγ inhibition promoted pyroptosis by regulating members of the gasdermin family in macrophages. Mechanistically, REGγ directly degraded Bim, a factor of the Bcl-2 family that can inhibit the cleavage of GSDMD/E, ultimately preventing the occurrence of pyroptosis. Furthermore, cecal ligation and puncture (CLP)-induced sepsis model mice showed downregulation of REGγ at both the RNA and protein levels. Gasdermin-mediated pyroptosis was augmented in REGγ-knockout mice, and these mice exhibited more severe sepsis-related tissue injury. More importantly, we found that REGγ expression was downregulated in clinical sepsis samples, such as those from patients with Pseudomonas aeruginosa (PA) infection. Finally, PA-infected mice showed decreased REGγ levels in the lung. In summary, our study reveals that the REGγ-Bim-GSDMD/E pathway is a novel regulatory mechanism of pyroptosis in sepsis-related tissue injury.

Pyroptosis in health and disease: mechanisms, regulation and clinical perspective

Pyroptosis is a type of programmed cell death characterized by cell swelling and osmotic lysis, resulting in cytomembrane rupture and release of immunostimulatory components, which play a role in several pathological processes. Significant cellular responses to various stimuli involve the formation of inflammasomes, maturation of inflammatory caspases, and caspase-mediated cleavage of gasdermin. The function of pyroptosis in disease is complex but not a simple angelic or demonic role. While inflammatory diseases such as sepsis are associated with uncontrollable pyroptosis, the potent immune response induced by pyroptosis can be exploited as a therapeutic target for anti-tumor therapy. Thus, a comprehensive review of the role of pyroptosis in disease is crucial for further research and clinical translation from bench to bedside. In this review, we summarize the recent advancements in understanding the role of pyroptosis in disease, covering the related development history, molecular mechanisms including canonical, non-canonical, caspase 3/8, and granzyme-mediated pathways, and its regulatory function in health and multiple diseases. Moreover, this review also provides updates on promising therapeutic strategies by applying novel small molecule inhibitors and traditional medicines to regulate pyroptosis. The present dilemmas and future directions in the landscape of pyroptosis are also discussed from a clinical perspective, providing clues for scientists to develop novel drugs targeting pyroptosis.

CRLF1 bridges AKT and mTORC2 through SIN1 to inhibit pyroptosis and enhance chemo-resistance in ovarian cancer

Ovarian cancer, the second most leading cause of gynecologic cancer mortality worldwide, is challenged by chemotherapy resistance, presenting a significant hurdle. Pyroptosis, an inflammation-linked programmed cell death mediated by gasdermins, has been shown to impact chemoresistance when dysregulated. However, the mechanisms connecting pyroptosis to chemotherapy resistance in ovarian cancer are unclear. We found that cytokine receptor-like factor 1 (CRLF1) is a novel component of mTORC2, enhancing AKT Ser473 phosphorylation through strengthening the interaction between AKT and stress-activated protein kinase interacting protein 1 (SIN1), which in turn inhibits the mitogen-activated protein kinase kinase kinase 5 (ASK1)-JNK-caspase-3-gasdermin E pyroptotic pathway and ultimately confers chemoresistance. High CRLF1-expressing tumors showed sensitivity to AKT inhibition but tolerance to cisplatin. Remarkably, overexpression of binding-defective CRLF1 variants impaired AKT-SIN1 interaction, promoting pyroptosis and chemosensitization. Thus, CRLF1 critically regulates chemoresistance in ovarian cancer by modulating AKT/SIN1-dependent pyroptosis. Binding-defective CRLF1 variants could be developed as tumor-specific polypeptide drugs to enhance chemotherapy for ovarian cancer.

Cell Death: Mechanisms and Potential Targets in Breast Cancer Therapy

Breast cancer (BC) has become the most life-threatening cancer to women worldwide, with multiple subtypes, poor prognosis, and rising mortality. The molecular heterogeneity of BC limits the efficacy and represents challenges for existing therapies, mainly due to the unpredictable clinical response, the reason for which probably lies in the interactions and alterations of diverse cell death pathways. However, most studies and drugs have focused on a single type of cell death, while the therapeutic opportunities related to other cell death pathways are often neglected. Therefore, it is critical to identify the predominant type of cell death, the transition to different cell death patterns during treatment, and the underlying regulatory mechanisms in BC. In this review, we summarize the characteristics of various forms of cell death, including PANoptosis (pyroptosis, apoptosis, necroptosis), autophagy, ferroptosis, and cuproptosis, and discuss their triggers and signaling cascades in BC, which may provide a reference for future pathogenesis research and allow for the development of novel targeted therapeutics in BC.

CircPDIA3/miR-449a/XBP1 feedback loop curbs pyroptosis by inhibiting palmitoylation of the GSDME-C domain to induce chemoresistance of colorectal cancer

Although oxaliplatin (OXA) is widely used in the frontline treatment of colorectal cancer (CRC), CRC recurrence is commonly observed due to OXA resistance. OXA resistance is associated with a number of factors, including abnormal regulation of pyroptosis. It is therefore important to elucidate the abnormal regulatory mechanism underlying pyroptosis. Here, we identified that the circular RNA circPDIA3 played an important role in chemoresistance in CRC. CircPDIA3 could induce chemoresistance in CRC by inhibiting pyroptosis both in vitro and in vivo. Mechanistically, RIP, RNA pull-down and co-IP assays revealed that circPDIA3 directly bonded to the GSDME-C domain, subsequently enhanced the autoinhibitory effect of the GSDME-C domain through blocking the GSDME-C domain palmitoylation by ZDHHC3 and ZDHHC17, thereby restraining pyroptosis. Additionally, it was found that the circPDIA3/miR-449a/XBP1 positive feedback loop increased the expression of circPDIA3 to induce chemoresistance. Furthermore, our clinical data and patient-derived tumor xenograft (PDX) models supported the positive association of circPDIA3 with development of chemoresistance in CRC patients. Taken together, our findings demonstrated that circPDIA3 could promote chemoresistance by amplifying the autoinhibitory effect of the GSDME-C domain through inhibition of the GSDME-C domain palmitoylation in CRC. This study provides novel insights into the mechanism of circRNA in regulating pyroptosis and providing a potential therapeutic target for reversing chemoresistance of CRC.

Gasdermins as evolutionarily conserved executors of inflammation and cell death

The gasdermins are a family of pore-forming proteins that have recently emerged as executors of pyroptosis, a lytic form of cell death that is induced by the innate immune system to eradicate infected or malignant cells. Mammalian gasdermins comprise a cytotoxic N-terminal domain, a flexible linker and a C-terminal repressor domain. Proteolytic cleavage in the linker releases the cytotoxic domain, thereby allowing it to form β-barrel membrane pores. Formation of gasdermin pores in the plasma membrane eventually leads to a loss of the electrochemical gradient, cell death and membrane rupture. Here we review recent work that has expanded our understanding of gasdermin biology and function in mammals by revealing their activation mechanism, their regulation and their roles in autoimmunity, host defence and cancer. We further highlight fungal and bacterial gasdermin pore formation pointing to a conserved mechanism of cell death induction.