A bioorthogonal system reveals antitumour immune function of pyroptosis

Gasdermin E links tumor cell-intrinsic nucleic acid signaling to proinflammatory cell death for successful checkpoint inhibitor cancer immunotherapy

Durable clinical responses to immune checkpoint inhibitors (ICI) are limited to a minority of patients, and molecular pathways that modulate their efficacy remain incompletely defined. We have recently shown that activation of the innate RNA-sensing receptor RIG-I and associated apoptotic tumor cell death can facilitate tumor immunosurveillance and -therapy, but the mechanism that drives its immunogenicity remained unclear. We here show that intratumoral activity of the pore-forming protein gasdermin E (GSDME) links active RIG-I signaling and apoptotic cell death in tumor cells to inflammatory pyroptosis. Activation of tumor-intrinsic RIG‑I triggered cleavage of GSDME, pore formation, loss of cell membrane integrity and leakage of cytosolic components from dying tumor cells. Tumor antigen cross-presentation by dendritic cells and subsequent expansion of cytotoxic T cells strongly relied on tumor-intrinsic GSDME activity. In preclinical murine cancer models, defective GSDME signaling rendered tumors resistant to ICI therapy. Epigenetic reprogramming with upregulation of Gdsme enhanced the susceptibility of tumor cells to inflammatory cell death and immunotherapy. In humans, transcriptome analysis of melanoma samples showed strong correlation between genetic activity of the RIG-I and pyroptosis pathways. In melanoma patients, high transcriptional activity of a pyroptosis gene set was associated with prolonged survival and beneficial response to ICI therapy. In summary, our data show that GSDME links RIG-I and apoptotic signaling to inflammatory cell death, thereby driving its immunogenicity and responsiveness to ICI. A deeper understanding of these pathways may allow for the development of novel combined modality approaches to improve ICI treatment responses in cancer patients.

Two-photon photosensitizer for specific targeting and induction of tumor pyroptosis to elicit systemic immunity-boosting anti-tumor therapy

Photodynamic therapy (PDT) has garnered increasing attention in cancer treatment due to its precise spatiotemporal selectivity and non-invasive nature. However, several challenges, including the inability of photosensitizers to discriminate between tumor and healthy tissues, as well as the limited tissue penetration depth of light sources, impede its broader application. To surmount these impediments, our research introduces a two-photon photosensitizer (TPSS) that specifically targets tumor overexpressing carbonic anhydrase IX (CA IX), thereby exhibiting exceptional specificity for tumor cells. Under two-photon laser stimulation, TPSS generates a large amount of reactive oxygen species (ROS), inducing cell pyroptosis and subsequently triggering a strong anti-tumor immune response. Additionally, proteomics analysis provides compelling evidence to elucidate the anti-tumor mechanism of TPSS in vivo. Through comprehensive immune assessments, TPSS under two-photon laser irradiation effectively activates both the innate and adaptive immune systems, efficiently suppressing the proliferation of distant metastatic tumors, underscoring its considerable therapeutic potential. Collectively, this study provides a viable strategy to overcome the limitations of PDT, highlighting the prospects of two-photon excitation photosensitizers.

Tunable ion-release biodegradable nanoparticles enhanced pyroptosis for tumor immunotherapy

Pyroptosis is an effective strategy for inducing inflammatory responses in 'cold' tumors, boosting the efficacy of immunotherapy. Although biodegradable inorganic nanoparticles (BINPs) show great potential in pyroptosis by releasing ions to break intracellular homeostasis, the limited intracellular ion release efficiency restricts pyroptosis level and subsequent immune activation. Herein, by heterovalent substitution strategy, a series of Na3ZrF7:x%Yb3+ (NZF:x%Yb, x = 0, 9, and 18) BINPs with tunable intracellular ion release efficiency are synthesized for enhanced pyroptosis and tumor immunotherapy. Specifically, the size of NZF:x%Yb3+ gradually decrease with increasing Yb3+ -doped and smaller NZF:x%Yb presents a higher degradation rate and cellular uptake ability, enabling improved intracellular ion release efficiency. This leads to drastic intracellular homeostasis stress and abundant ROS generation, thereby provoking enhanced caspase-1-related pyroptosis. Antitumor experiments in triple-negative breast cancer model confirm that the ultra-small NZF:x%Yb (NZF:18%Yb) with the highest intracellular ion release efficiency shown the most effective antitumor ability, and significant inhibition of distal tumor. This study reveals precise control over the size of NZF:x%Yb is especially vital to achieving pyroptosis-induced immunotherapy, which offers a new perspective for the design of BINPs.

An Endoplasmic Reticulum Stress-Specific Nanoinducer Selectively Evokes Type-II Immunogenic Cell Death for Pyroptotic Cancer Immunotherapy

Specific induction of endoplasmic reticulum (ER) stress-initiated type-II immunogenic cell death (ICD) shows great potential in boosting tumor immunogenicity and anti-tumor immunotherapy. However, it remains challenging to selectively provoke type-II ICD, due to the lack of highly efficient ER targeting strategy. Here, a pH/Cathepsin-Activatable Nanoplatform (PCAN) is reported to specifically photo-induce ER stress (PCANER) and type-II ICD for cancer immunotherapy. PCANER integrates the long-circulating properties of nanomedicines with pH/cathepsin B dual-gated design, exhibiting excellent ER targeting with a colocalization efficacy of 83% in cancer tissues. Through directly intensifying glucose-regulated protein 78 and calreticulin exposure, PCANER augments type-II ICD and pyroptotic cancer cell death with high immune priming to cascade-amplify the cancer-immunity cycle, while the mild type-I ICD induced by lysosome stress (PCANLy) exhibits negligible antitumor efficacy. By leveraging the spatiotemporal subcellular organelle targeting of PCAN technology, this study achieves precise tuning of the type of ICD and cellular pyroptosis-based cancer therapy. This study offers new insights into the design of organelle level-targeted nanomedicines, paving the way for dissecting and modulating the cell death mechanism to boost cancer immunotherapy.

Cucurbitacin B induces oral squamous cell carcinomapyroptosis via GSDME and inhibits tumour growth

BACKGROUND

Pyroptosis, a form of programmed cell death, has been shown to induce anti-tumour immunity and inhibit tumour growth. Oral squamous cell carcinoma (OSCC), a prevalent malignant tumour, could benefit from pyroptosis induction as a therapeutic strategy. Cucurbitacin B (CuB), a natural compound derived from various plants, exhibits broad anti-tumour activity. However, whether CuB can exert its anti-tumour effects in OSCC through pyroptosis remains unexplored.

RESULTS

CuB significantly inhibited the proliferation of OSCC cells, induced pyroptosis, and elevated the levels of inflammatory factors in the cell supernatant. Bioinformatics analysis predicted the potential role of pyroptosis in OSCC, which was subsequently validated in a 4NQO-induced OSCC mouse model. The results demonstrated that CuB not only exerted tumour-inhibitory effects but also increased the infiltration of CD8+ T cells in the peritumoural region. To elucidate the mechanism of CuB-induced pyroptosis, STAT3 was identified as a key target of CuB in OSCC, with its expression upregulated in tumour tissues. Further experiments revealed that CuB induced pyroptosis by suppressing STAT3 expression and promoting the cleavage of caspase-3 and Gasdermin-E (GSDME).

CONCLUSION

CuB triggers OSCC pyroptosis through the STAT3/caspase-3/GSDME pathway, enhancing peritumoural CD8+ T cell infiltration and offering a novel strategy to boost tumour immunotherapy efficacy.

Co-encapsulation of norcantharidin prodrugs and lomitapide in nanoparticles to regulate CCL4 expression by inhibiting Wnt/β-catenin pathway for improved anti-tumor immunotherapy

In the absence of tumor antigen specificity, direct chemokine administration carries the risk of significant "on-target, off-tumor" toxicities, highlighting the need for small-molecule approaches with reduced immunogenicity. This study investigates the synergistic potential of norcantharidin (NCTD) and lomitapide (lomi) in selectively restoring CCL4 expression by deactivating the tumor intrinsic β-catenin pathway. Due to its similar lipophilicity to lomi and potential to suppress β-catenin, NCTD prodrug (C12) was selected to be co-encapsulated with lomi in a nanoparticle-mediated co-delivery system (NP"C12 + lomi"). The NP"C12 + lomi" formulation exhibited a high encapsulation rate, uniform particle size, and suitability for therapeutic use. It effectively inhibited the proliferation of 4T1 cells and restored CCL4 expression. In both primary breast tumor and surgically resected tumor mouse models, NP"C12 + lomi" significantly increased the proportion of CD8+ cells in primary tumors, blood, and lung metastases, approximately doubling their presence. This led to a prolongation of median survival in mice to 59 days. Furthermore, when combined with an immune checkpoint inhibitor, NP"C12 + lomi" substantially inhibited tumor growth and lung metastasis without affecting body weight or causing major tissue or organ damage. This was attributed to the controlled dissociation of the nanoparticle and the subsequent modulation of C12 and lomi, which mitigated CCL4-related toxicity. This study provides valuable insights into the safe production of chemokines using a small-molecule pair through a nanosystem and presents a robust chemo-immunological cascade therapy strategy, demonstrating significant efficacy against malignant metastatic tumors.

In Situ Generation of Pyroptosis Inducer Mediated by Intracellular Labile Copper Pool for Safe and Robust Antitumor Immunotherapy

Pyroptosis has garnered increasing interest in the realm of cancer immunotherapy. Utilizing reactive oxygen species (ROS) to trigger oxidative stress is considered an effective strategy for promoting pyroptosis. However, existing catalytic nanoparticles used as pyroptosis inducers contain heavy metals, which inevitably cause potential side effects on normal tissues due to their high toxicity and off-target effects. Herein, a labile copper pool-mediated in situ pyroptosis inducer was designed and developed using a hydrogen-bonded organic framework (HOF)-based nanoplatform to achieve safe and robust antitumor immunotherapy. The nanoplatform could target mitochondria and elevate labile Cu2+ levels in cells, implementing the in situ synthesis of a pyroptosis inducer through the formation of catalytic nanoparticles with peroxidase (POD) and superoxide dismutase (SOD)-mimicking activities. Our results confirmed that the nanoplatform could generate high levels of ROS, resulting in pyroptotic cell death. When combined with antiprogrammed death receptor 1 therapy (αPD-1), the pyroptosis inducer exhibited excellent antitumor capacity in tumor models. Meanwhile, it exhibited minimal toxicity to healthy tissues due to the low intracellular copper concentration in normal cells. Overall, our work provides potential for the development of efficient and safe antitumor immunotherapy.

Circular RNAs in glioma progression: Fundamental mechanisms and therapeutic potential: A review

Gliomas are the most common primary malignant brain tumors, characterized by aggressive invasion, limited therapeutic options, and poor prognosis. Despite advances in surgery, radiotherapy, and chemotherapy, the median survival of glioma patients remains disappointingly low. Therefore, identifying glioma-associated therapeutic targets and biomarkers is of significant clinical importance. Circular RNAs (circRNAs) are a class of naturally occurring long non-coding RNAs (lncRNAs), notable for their stability and evolutionary conservation. Increasing evidence indicates that circRNA expression is dysregulated in gliomas compared to adjacent non-tumor tissues and contributes to the regulation of glioma-related biological processes. Furthermore, numerous circRNAs function as oncogenes or tumor suppressors, mediating glioma initiation, progression, and resistance to temozolomide (TMZ). Mechanistically, circRNAs regulate glioma biology through diverse pathways, including acting as miRNA sponges, binding RNA-binding proteins (RBPs), modulating transcription, and even encoding functional peptides. These features highlight the potential of circRNAs as diagnostic and prognostic biomarkers, as well as therapeutic targets for glioma. This review summarizes the dysregulation and functions of circRNAs in glioma and explores key mechanisms through which they mediate tumor progression, including DNA damage repair, programmed cell death (PCD), angiogenesis, and metabolic reprogramming. Our aim is to provide a comprehensive perspective on the multifaceted roles of circRNAs in glioma and to highlight their potential for translational application in targeted therapy.

Self-Assembly of Ru3-Aptamer Nanoparticles Triggers Pyroptosis through Photoredox Catalysis of NADH and Lysosomal Disruption

Photodynamic therapy (PDT) can induce tumor cell death. Ru3, a metal-based photosensitizer, features a high positive charge, a long triplet excited-state lifetime, and an excellent PDT activity. The aptamer AS1411, known for its ability to selectively bind to nucleolin (which is overexpressed in tumor cells), self-assembled with Ru3 into nanoparticles termed Ru3ApNPs. These nanoparticles specifically target SiHa tumor cells. Upon light irradiation, Ru3ApNPs increase intracellular ROS levels, catalyze NADH redox reactions, and induce lysosomal disruption, ultimately triggering pyroptosis in tumor cells. Notably, Ru3ApNPs demonstrate excellent tumor penetration in 3D multicellular spheroids (MCSs) of SiHa cells and effectively inhibit their growth under light exposure. Ru3ApNPs exhibit a mechanism of action distinct from that of traditional PDT. Furthermore, under light irradiation, Ru3ApNPs can effectively inhibit the growth of distant tumors and induce systemic immune responses in mice. Our data suggest that Ru3ApNPs can be developed as promising targeted therapeutic agents in the future.

Self-Driven CuAAC Reaction Catalyzed by Photosensitive Biohybrids Energized by Lactate for Boosting Cancer Immunotherapy

As a typical bioorthogonal reaction, the copper (I) catalyzed azide-alkyne 1,3-cycloaddition (CuAAC) reaction strongly depends on the reducing agents and the rate of the CuAAC reaction is far from sufficient to produce drug agents under physiological conditions. It is necessary and highly demanding to develop an efficient CuAAC reaction without using chemical reducing agents. Herein, inspired by the extracellular electron transfer (EET) mechanisms of the electroactive bacteria within the realm of synthetic biology, a photo-assisted targeting electroactive bacteria equipped bioorthogonal catalyst system for boosting cancer immunotherapy is constructed. The bacteria specifically anaerobically catabolize lactate at the tumor site, accompanied by transferring electrons to the bioorthogonal catalyst, thereby triggering the CuAAC reaction to produce active drugs in situ. Strikingly, under illumination, the photoelectrons generated by attached AuNPs can be transported into bacterial cytoplasm to accelerate the CuAAC reaction by promoting cellular metabolism. The biohybrid enables synergistic immunogenic cell death (ICD), immune checkpoint blockade (ICB) immunotherapy and alleviation of immunosuppressive microenvironment. Ingeniously, ICD and lactate consumption both boost the efficacy of ICB immunotherapy. Overall, the system provides a bridge between the tumor metabolism and CuAAC reaction through bacterial respiration, offering fascinating opportunities for controlled synthesis of active molecules by bioorthogonal catalysis.

Defects in the necroptosis machinery are a cancer resistance mechanism to checkpoint inhibitor immunotherapy

BACKGROUND

Immune checkpoint inhibitors (ICIs) of programmed cell death protein-1 (PD-1) or cytotoxic T-lymphocytes-associated protein 4 (CTLA-4) reinvigorate strong polyclonal T-cell immune responses against tumor cells. For many patients, these therapies fail because the development of spontaneous immune responses is often compromised, as the tumor microenvironment (TME) lacks proinflammatory signals resulting in suboptimal activation of antigen-presenting cells (APCs). Necroptosis is a special form of programmed cell death associated with leakage of inflammatory factors that can lead to APC maturation. However, it is unclear to which extent functional necroptosis in tumor cells contributes to ICI immunotherapy.

METHODS

With genetically engineered tumor cell lines that lack specific components of the necroptosis machinery (mixed lineage kinase domain-like pseudokinase (MLKL), receptor interacting protein kinase 3 (RIPK3)), we addressed the importance of necroptotic tumor cell death for the efficacy of ICI immunotherapy in murine models. Preclinical data were aligned with genome-wide transcriptional programs in patient tumor samples at diagnosis and during ICI treatment for the activity of these pathways and association with treatment outcome.

RESULTS

Mice bearing MLKL-deficient or RIPK3-deficient tumors failed to control tumor growth in response to anti-PD-1/anti-CTLA-4 immunotherapy. Mechanistically, defects in the necroptosis pathway resulted in reduced tumor antigen cross-presentation by type 1 conventional dendritic cells (DCs) in tumor-draining lymph nodes, and subsequently impaired immunotherapy-induced expansion of circulating tumor antigen-specific CD8+ T cells and their accumulation and activation in the TME. In vitro, co-culture of tumor cells undergoing necroptotic but not apoptotic programmed cell death resulted in increased uptake by phagocytic cells, associated with maturation and activation of DCs. Treatment of tumors with the epigenetic modulator azacytidine enhanced intrinsic transcriptional activity of the necroptosis machinery, and hence their susceptibility to ICI immunotherapy. In humans, transcriptome analysis of melanoma samples revealed a strong association between high expression of MLKL and prolonged overall survival and durable clinical response to immunotherapy with anti-PD-1 and/or anti-CTLA-4 checkpoint inhibitors.

CONCLUSIONS

Defective necroptosis signaling in tumor cells is a cancer resistance mechanism to ICI immunotherapy. Reversion of epigenetic silencing of the necroptosis pathway can render tumors susceptible to checkpoint inhibition.

Targeting pyroptosis for cancer immunotherapy: mechanistic insights and clinical perspectives

Pyroptosis is a distinct form of programmed cell death characterized by the rupture of the cell membrane and robust inflammatory responses. Increasing evidence suggests that pyroptosis significantly affects the tumor microenvironment and antitumor immunity by releasing damage-associated molecular patterns (DAMPs) and pro-inflammatory mediators, thereby establishing it as a pivotal target in cancer immunotherapy. This review thoroughly explores the molecular mechanisms underlying pyroptosis, with a particular focus on inflammasome activation and the gasdermin family of proteins (GSDMs). It examines the role of pyroptotic cell death in reshaping the tumor immune microenvironment (TIME) involving both tumor and immune cells, and discusses recent advancements in targeting pyroptotic pathways through therapeutic strategies such as small molecule modulators, engineered nanocarriers, and combinatory treatments with immune checkpoint inhibitors. We also review recent advances and future directions in targeting pyroptosis to enhance tumor immunotherapy with immune checkpoint inhibitors, adoptive cell therapy, and tumor vaccines. This study suggested that targeting pyroptosis offers a promising avenue to amplify antitumor immune responses and surmount resistance to existing immunotherapies, potentially leading to more efficacious cancer treatments.

Molecular mechanisms underlying the anti-Colon Cancer effects of Caulerpa lentillifera polysaccharides (CLP)

Colon cancer (CC) ranks is the second leading cause of cancer-related deaths globally. Despite chemotherapy being a primary treatment its effectiveness significantly declines in advanced in stage. Emerging evidence suggests that dietary components particularly polysaccharides, play a role in CC progression. This study employed multi-omics and network pharmacology to elucidate the mechanisms underlying the apoptotic effects of Caulerpa lentillifera polysaccharide (CLP) in CC, validated through in vitro and in vivo experiments. Transcriptomics and network pharmacology analysis identified the p53/Bax/Caspase-3 pathway as a key regulatory axis. Further targeted analysis of amino acid metabolism revealed that CLP significantly decreased intracellular aspartate (Asp) levels. Additionally, reactive oxygen species (ROS) accumulation was detected in cells. CLP treatment reduced Asp content, leading to ROS accumulation, which activated the p53/Bax/Caspase-3 pathway, triggering apoptosis. In vivo, CLP effectively inhibited tumor growth in BALB/c mice bearing CT26 colon cancer cells. These findings suggest that CLP exerts anti-colon cancer effects by modulating amino acid metabolism and inducing apoptosis via the p53/Bax/Caspase-3 axis, providing a promising therapeutic strategy for CC.

Engineered bacterial membrane biomimetic covalent organic framework as nano-immunopotentiator for cancer immunotherapy

The cellular uptake and tissue dispersion efficiency of nanomedicines are crucial for realizing their biological functionality. As a cutting-edge category of nanomedicine, covalent organic frameworks (COFs)-based photosensitizers, have been extensively employed in cancer phototherapy in recent years. However, the inherent aggregation tendency of COFs hinders their uptake by tumor cells and dispersion within tumor tissues, thereby limiting their therapeutic efficacy. In this study, we employed Fusobacterium nucleatum (F.n.), a prevalent intratumoral bacterium, to construct a bacterium membrane-wrapped COF, COF-306@FM, which is readily taken up by cancer cells and uniformly dispersed within tumor tissues. Meanwhile, the F.n. membrane can also serve as an immune adjuvant to warm up the "cold" tumor immune microenvironment by enhancing the CD8+ T and B cells infiltration, and inducing the formation of tumor-located tertiary lymphoid structures. Consequently, the response rate of αPD-L1 immunotherapy was drastically promoted to efficiently prevent tumor metastasis and recurrence, causing 84.6 % distant tumor inhibition and complete suppression of tumor metastasis. In summary, this innovative approach not only enhances the therapeutic potential of COFs but also opens up new avenues for integrating microbial and nanotechnological strategies in cancer treatment.

An optimized integrin α6-targeted peptide capable of delivering toxins for melanoma treatment

BACKGROUND

Peptide-based therapeutics for melanoma have received increasing attention in medical research. However, the local delivery of such therapeutics poses unique challenges. Cell-penetrating peptides (CPPs) with the ability to selectively enter cancer cells, with sufficient stability and increased endosomal escape mechanisms, can provide a new and improved delivery strategy for therapeutic agents for treating cancer.

METHODS

We developed a new combination strategy for the synthesis of penetrating peptides functionalized with targeting of integrin α6. The linear peptide S5 was multimerized with 4 copies in linear sequential order spaced by GSG between each copy to yield the 4S5 peptide. The multimerized 4S5 peptide coupled with an intracellular delivery peptide (N) and endosomal escape peptide (G) was separated by a GGS spacer. This optimized peptide was called 4S5NG. The 4S5NG, EGFP or PE24 peptide-protein conjugates were purified via a C-terminal His-tag. The uptake efficacy, intracellular distribution and integrin α6-targeting ability of these 4S5NG peptides were systematically characterized via IncuCyte, flow cytometry and in vivo imaging using 4S5NG-Cy5 or 4S5NG-EGFP. Moreover, 4S5NG-incorporated Pseudomonas aeruginosa (PE24) exotoxin A generated therapeutic peptides. The antitumor efficacy and underlying mechanism were studied in cell lines and a mouse model. In addition, the effect of 4S5NG-PE24 on antitumor immunity of a healthy immune system was investigated via a mouse model.

RESULTS

Images of living cells and mice indicated that 4S5NG accumulated at tumor sites in vitro and in vivo and was much more effective than the S5 and 4S5 peptides. 4S5NG-PE24 induced cell pyroptosis in integrin α6-expressing melanoma through the caspase 3/gasdermin E (GSDME) signaling pathway in the absence of histological alterations in other organs. 4S5NG-PE24 also promoted the response rate of programmed cell death protein-1 (PD-1) checkpoint blockade to increase antitumor efficacy.

CONCLUSIONS

Collectively, these results highlight the potential use of 4S5NG to deliver the toxin PE24 to selectively eliminate integrin α6+ cells in melanoma, which may represent a novel treatment approach for melanoma patients.

Gasdermins in pyroptosis, inflammation, and cancer

Pyroptosis is a type of programmed inflammatory cell death characterized by balloon-like swelling, membrane rupture, and the release of inflammatory cytokines and danger signals. Pyroptosis is directly triggered by activated gasdermins (GSDMs) which bind to membrane phospholipids, oligomerize, and form pores in cell membranes. GSDM activation is mediated by various effector proteases via cleavage of the linker region or post-translational modification to release the active N-terminal fragment in response to a variety of pathogenic or intrinsic danger signals. GSDM-mediated pyroptosis is involved in the pathogenesis of an array of infectious and inflammatory diseases and cancers. This review discusses recent advances related to the physiological and pathological functions of GSDM-mediated pyroptosis, as well as therapeutic strategies targeting pyroptosis.

Silver Molybdate Nanoparticles for Enhanced Tumor Immunotherapy through Pyroptosis Conversion and Ferroptosis Induction

Pyroptosis holds great potential in tumor therapy due to its strong immunogenicity. Several strategies, including ion interference therapy (IIT), are developed to induce pyroptosis. However, the mechanism by which metal oxoanions induced pyroptosis remained unclear. It was reported that MoO4 2- ions could stimulate immune responses, but their pyroptosis-inducing mechanisms were not fully understood. Herein, we synthesized uniform and dispersed silver molybdate (Ag2MoO4) nanoparticles (AMO) via a solvothermal method. AMO responded to H2O2 and glutathione (GSH) stimuli, releasing Ag+ and MoO4 2- ions, generating reactive oxygen species (ROS), and depleting GSH, thereby inducing ferroptosis and pyroptosis. The MoO4 2- also inhibited cell migration and upregulated GSDME expression, converting apoptosis into caspase-3/GSDME-mediated pyroptosis. Additionally, DNA damage and ROS activated the cGAS-STING pathway, enhancing innate immunity. In vivo experiments demonstrated that the combination of AMO and the immune checkpoint inhibitor αPD-1 significantly inhibited tumor growth. This combination promoted dendritic cells (DCs) maturation, increased effector T cell numbers, induced M1 macrophage polarization, and alleviated immunosuppression. This study contributed to a deeper understanding of metal oxoanion-mediated pyroptosis, supporting its potential application in cancer immunotherapy.

HIC1 suppresses Tumor Progression and Enhances CD8+ T Cells Infiltration Through Promoting GSDMD-induced Pyroptosis in Gastric Cancer

Recently, immune checkpoint blockade treatment has made remarkable strides in combatting malignancies, including gastric cancer (GC). Nonetheless, the efficacy of immunotherapy in GC patients remains constrained, warranting further exploration of the underlying molecular mechanisms to improve therapeutic outcomes. Hypermethylated in cancer 1 (HIC1) is acknowledged as a transcriptional regulator crucial for multiple aspects of cell development, yet its role in antitumor immune responses remains incompletely understood. This investigation reveals a significant downregulation of HIC1 in gastric cancer, correlating with a less favorable prognosis. Overexpression of HIC1 promotes the initiation of cell pyroptosis. Mechanistically, gasdermin D (GSDMD), a pivotal executor of pyroptosis, is identified as a downstream target of HIC1 and activated by HIC1 at the transcriptional level. Subsequent cleavage of the GSDMD N-terminal region punctures the cell membrane, instigating pyroptosis and releasing inflammatory factors. Furthermore, HIC1 augments the infiltration of CD8+ T cells to counteract immune evasion. The combinatorial approach of HIC1 overexpression with PD-L1 antibody demonstrates a synergistic therapeutic impact in treating GC. Additionally, c-Jun activation domain-binding protein 1 (Jab1) mediates the ubiquitylation and proteasomal degradation of HIC1 at Lys517. Ultimately, these findings underscore the potential of HIC1 as a promising immunotherapeutic target for the treatment of GC.

Long non-coding RNA in the regulation of cell death in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the predominant form of primary liver cancer, accounting for 90% of all cases. Currently, early diagnosis of HCC can be achieved through serum alpha-fetoprotein detection, B-ultrasound, and computed tomography scanning; however, their specificity and sensitivity are suboptimal. Despite significant advancements in HCC biomarker detection, the prognosis for patients with HCC remains unfavorable due to tumor heterogeneity and limited understanding of its pathogenesis. Therefore, it is crucial to explore more sensitive HCC biomarkers for improved diagnosis, monitoring, and management of the disease. Long non-coding RNA (lncRNA) serves as an auxiliary carrier of genetic information and also plays diverse intricate regulatory roles that greatly contribute to genome complexity. Moreover, investigating gene expression regulation networks from the perspective of lncRNA may provide insights into the diagnosis and prognosis of HCC. We searched the PubMed database for literature, comprehensively classified regulated cell death mechanisms and systematically reviewed research progress on lncRNA-mediated cell death pathways in HCC cells. Furthermore, we prospectively summarize its potential implications in diagnosing and treating HCC.

In Situ Secondary Self-Assembly of Near-Infrared II J-Aggregates: A Novel Phototheranostic Strategy for Inducing Tumor Pyroptosis

Pyroptosis, a programmed cell death mechanism that bypasses apoptosis resistance and triggers tumor-specific immune responses, has gained much attention as a promising approach to cancer therapy. Despite enhancing tumor accumulation and extending the circulation of small-molecule drugs, nanomedicines still face significant challenges, including poor tissue penetration, tumor resistance, and hypoxic microenvironments. To overcome these challenges, a novel near-infrared II (NIR-II) J-aggregate-based nanomedicine is designed, leveraging an in situ secondary self-assembly strategy to fabricate highly targeted nanoparticles (MSDP NPs). These nanomedicines trigger pyroptosis by generating type I reactive oxygen species, especially superoxide anions, while simultaneously activating photoimmunotherapy. In vivo studies demonstrate that MSDP NPs achieve efficient tumor penetration and prolong tumor retention, which is facilitated by the J-aggregate-driven formation of microscale spindle-shaped fibrillar bundles through in situ secondary self-assembly at the tumor site. This unique structural transformation enhances nanomedicine accumulation in tumor tissues, enabling robust NIR-II fluorescence imaging and improving therapeutic efficacy even in hypoxic tumor microenvironments. This study provides an innovative phototheranostic strategy that utilizes the in situ secondary self-assembly of NIR-II J-aggregates to induce tumor pyroptosis, offering a potential solution to the limitations of current nanomedicines in cancer therapy.

Therapeutic connections between pyroptosis and paclitaxel in anti-tumor effects: an updated review

As a form of inflammation-associated cell death, pyroptosis has gained widespread attention in recent years. Accumulating evidence indicates that pyroptosis regulates tumor growth and is associated with autoimmune disorders and inflammatory response. Paclitaxel, a traditional Chinese medicine, usually induces death of cancer cells as a chemotherapeutic agent. Previous studies have revealed that paclitaxel can exert an anti-tumor effect through a variety of cell death mechanisms, of which pyroptosis plays a pivotal role in inhibiting tumor growth and enhancing anti-tumor immunity. In this review, we summarize the current advances in therapeutic connections between pyroptosis and paclitaxel in anti-tumor effects.

Caerin 1.1 and 1.9 peptides induce acute caspase 3/GSDME-mediated pyroptosis in epithelial cancer cells

Caerin peptides exhibit a dual role in cancer treatment by directly killing cancer cells and modulating the tumour microenvironment to enhance anti-tumour immunity. This study investigates the mechanisms underlying caerin 1.1/1.9-induced acute cell death in epithelial cancer cells and explores their therapeutic potential. HeLa, A549, and Huh-7 cancer cell lines were treated with caerin 1.1/1.9 peptides. Morphological observations, flow cytometry, lactate dehydrogenase (LDH) release, and IL-18 secretion assays revealed the occurrence of pyroptosis following treatment. Specifically, a 1-h treatment with caerin 1.1/1.9 induced pyroptosis in HeLa, A549, and Huh-7 cells, characterised by cell swelling, membrane bubbling, and the release of IL-18 and LDH. Western blotting confirmed the upregulation of pyroptosis markers, including caspase-3, cleaved caspase-3, and GSDME-N fragments. These findings highlight the significant role of caerin peptides in inducing acute pyroptosis, a form of programmed cell death that enhances the immunogenicity of dying cancer cells, thus potentially improving the effectiveness of immunotherapies. This research underscores the therapeutic potential of caerin 1.1/1.9 peptides in cancer treatment, providing a foundation for developing new anti-cancer strategies that leverage both direct cytotoxic effects and immune modulation to achieve more effective and sustained anti-tumour responses.

Fluoroalkane Engineered Magnetic Vectors Unlock the Potential of Gasdermin in Vivo Delivery for Pyroptosis Induced Cancer Therapy

Pyroptosis, a programmed necrotic cell death mediated by gasdermin, can activate strong immune responses and serve as a potential target for cancer therapy. Nevertheless, the relatively large molecular size and negative surface charge of gasdermin impede them from effectively intracellular delivery and directly inducing pyroptosis. Here, a cytosolic protein delivery system, fluorinated iron oxide nanoparticles (FIONPs) is reported, which can self-assemble with active gasdermin A3 protein (GSDMA3) via noncovalent interactions and effectively trigger pyroptosis in 4T1 cells. It is proved that the delivery system is versatile for various cargo proteins (ribonuclease A, saporin, β-galactosidase, and bovine serum albumin) with different isoelectric points and molecular weights, without compromising their biological activity in vitro. What's more, under magnetic drive, FIONPs facilitate active transport of GSDMA3 in vivo, further augmenting tumor suppression and immune response. Overall, magnetic-driven FIONPs provide an effective delivery system for intracellular protein transductions, and the application of the delivery system reveals that direct delivery of GSDMA3 significantly elicits robust antitumor immunity via the induction of pyroptosis.

Unlocking the Power of Photothermal Agents: A Universal Platform for Smart Immune NIR-Agonists for Precise Cancer Therapy

Selective ablation of tumor cells allows safe eradication, thereby minimizing off-target damage, while specifically inducing immunogenic cell death (ICD) rather than commonly non-immunogenic apoptosis of tumor cells enables activation of anti-tumor immune response against residual cancer cells, including metastatic lesions. Herein, we present a general strategy leveraging a novel photothermal agent (PTA) that concomitantly enables precise tumor killing and activation of anti-tumor immunity. The unique PTA scaffold exhibits unexpected inherent endoplasmic reticulum (ER)-targeting capability and potent near-infrared (NIR) photothermal activity, inducing NIR-controlled immunogenic pyroptosis in various tumor cell lines via targeting ER stress in an oxygen-independent manner. Moreover, both ER-targeting and NIR-activity of our scaffold can be modulated on demand by chemical caging/uncaging, allowing quick activation with diverse biological and bioorthogonal molecular triggers. The potency of this universal platform is demonstrated via its application to develop a membrane protein-activatable NIR-agonist that selectively activates ICD in tumor sites while priming anti-tumor immunity, minimizing off-target effects and enhancing efficacy against mouse breast tumors. This versatile approach could lead to customization of various personalized and effective immune NIR-agonists for specific photoimmunotherapy applicable to diverse solid tumors.

Manipulation of cancer cell pyroptosis for therapeutic approaches: challenges and opportunities

Remarkable advances have been achieved following discoveries that gasdermins are the executioners of pyroptosis. The pyroptotic process consists a subcellular permeabilization phase and a cell lysis phase, the latter of which is irreversible. Besides immune cells, pyroptosis has also been observed in cancer cells, which exhibit distinct mechanisms compared to canonical immune cell pyroptosis. Although chronic cancer cell pyroptosis fuels tumor growth, intense pyroptotic cell death in tumor cells enhances anticancer immunity by promoting killer lymphocytes infiltration. Triggering pyroptosis in cancer cells is emerging as a promising strategy for cancer treatment. In this review, we introduce the process of cancer cell pyroptosis and its role in antitumor immunity, discuss the translation of these insights into therapies, and highlight current challenges and opportunities in the investigation of cancer cell pyroptosis.

Selective USP7 Inhibition Synergizes with MEK1/2 Inhibitor to Enhance Immune Responses and Potentiate Anti-PD-1 Therapy in NRAS-Mutant Melanoma

Targeted therapy for NRAS-mutant melanoma remains an unmet clinical need. We found that inhibiting USP7 with the selective ubiquitin-specific protease 7 inhibitor (USP7i) FT671 inhibited cell proliferation in NRAS-mutant melanoma cell lines. In addition, we identified and validated that knockout of TP53BP1, TP53, or CDKN1A conferred resistance to FT671, suggesting that the activation of a functional p53 signaling pathway is essential for the efficacy of USP7i. In Nras-mutant melanoma isograft models, FT671 treatment delayed tumor growth. Moreover, the combinatorial treatment with FT671 and MAPK/(extracellular signal-regulated kinase) kinase 1/2 inhibitor was synergistic and induced pyroptosis in vitro. In immunocompetent mice, the combined treatment profoundly suppressed tumor growth, prolonged survival, and enhanced intratumoral immune cell infiltration, particularly increasing the ratios of CD8+ T cells and mature dendritic cells, indicative of activated antitumor immunity. Notably, the triple combination of USP7i, MAPK/(extracellular signal-regulated kinase) kinase 1/2 inhibitor, and anti-PD-1 antibody resulted in durable tumor regression, with effects persisting beyond 80 days after treatment cessation. These findings establish USP7i + MAPK (extracellular signal-regulated kinase) kinase 1/2 inhibitor as a promising strategy for targeting NRAS, an 'undruggable' mutation in melanoma, and provide a strong rationale for the clinical development of USP7i plus MAPK (extracellular signal-regulated kinase) kinase 1/2 inhibitor as an adjuvant therapy to enhance anti-PD-1 immunotherapy in patients with NRAS-mutant melanoma.

Cell Death Modalities in Therapy of Melanoma

Melanoma, one of the most lethal cancers, demands urgent and effective treatment strategies. However, a successful therapeutic approach requires a precise understanding of the mechanisms underlying melanoma initiation and progression. This review provides an overview of melanoma pathogenesis, identifies current pathogenic factors contributing to mortality, and explores targeted therapy and checkpoint inhibitor therapy. Furthermore, we examine melanoma classification and corresponding therapies, along with advancements in various cell death mechanisms for melanoma treatment. We also discuss the current treatment status along with some drawbacks encountered during research stages such as resistance and metastasis.

Structurally diverse tetrahydroxanthone analogues from Paraconiothyrium sp. AC31 with pyroptosis induction through targeted inhibition of PARP1 in hepatocellular carcinoma cells

This study reports the isolation and characterization of six novel tetrahydroxanthone derivatives, paraconixanthones A - F (1-6), a new diphenyl ether (7), and thirteen known compounds (8-20) from the endophytic fungus Paraconiothyrium sp. AC31. The chemical structures were elucidated using NMR, MS, X-ray diffraction, and ECD analyses. Paraconixanthones A and B (1 and 2) represent the first examples of tetrahydroxanthone-benzoate dimers, suggesting a unique biosynthetic pathway. Compound 12 exhibited potent anti-proliferative activity against HepG2 hepatocellular carcinoma cells (IC50 = 1.19 μM), outperforming the standard therapy lenvatinib. Mechanistic studies revealed that compound 12 inhibits PARP1, leading to DNA damage, ROS accumulation, and caspase-3/GSDME-mediated pyroptosis. Additionally, it induces intrinsic apoptosis through BAX/BCL-2 modulation and caspase-7 activation. Meanwhile, GSDME deficiency treated with 12 exhibited the increased levels of PARP1 and caspase-3, supporting the cell death induced by 12 shifted from pyroptosis to apoptosis. These findings highlight the therapeutic potential of tetrahydroxanthones as selective agents targeting multiple cell death pathways in hepatocellular carcinoma, expanding the scope of natural product-based anti-cancer strategies.

Plasma Membrane Targeted Photodynamic Nanoagonist to Potentiate Immune Checkpoint Blockade Therapy by Initiating Tumor Cell Pyroptosis and Depleting Infiltrating B Cells

Immune checkpoint blockade (ICB) therapy has achieved remarkable benefits in the treatment of malignant tumors, but the clinical response rates are unsatisfied due to the low tumor immunogenicity and the abundant immunosuppressive cells. Herein, a plasma membrane targeted photodynamic nanoagonist (designated as PMTPN) is developed to potentiate ICB therapy by initiating tumor cell pyroptosis and depleting infiltrating B cells. PMTPN is composed of a rationally designed chimeric peptide sequence loaded with Bruton's tyrosine kinase inhibitor (Ibrutinib). Notably, PMTPN is capable of sequentially targeting tumor and tumor cell membrane to trigger immunogenic pyroptosis and cause overwhelming release of cytokines, promoting dendritic cells maturation, and cytotoxic T lymphocytes (CTLs) activation. Meanwhile, PMTPN can also deplete infiltrating B cells and reduce the secretion of interleukin-10 to decrease immunosuppressive regulatory T cells and enhance CTLs infiltration. Beneficially, the synergistic immune modulating characteristics of PMTPN potentiate ICB therapy to simultaneously eliminate primary and distant tumors. This study offers a promising strategy to elevate the immunotherapeutic response rate in consideration of the complex immunosuppressive factors.

Tandem-controlled lysosomal assembly of nanofibres induces pyroptosis for cancer immunotherapy

Pyroptosis has emerged as a promising approach for cancer immunotherapy. However, current pyroptosis inducers lack specificity for cancer cells and have a weak antitumour immune response. Here we report a tumour-specific nanoparticle (NP-NH-D5) that activates pyroptosis by disrupting lysosomes for cancer immunotherapy. NP-NH-D5 undergoes negative-to-positive charge reversal and nanoparticle-to-nanofibre transformation within tumour cell lysosomes through tandem response to extracellular matrix metallopeptidase-2 and intracellular reducing agents. The as-formed non-peptide nanofibres efficiently break the lysosomes and trigger gasdermin-D-mediated pyroptosis, leading to strong immunogenic cell death and alleviation of the immunosuppressive tumour microenvironment. In vivo, NP-NH-D5 inhibits orthotopic 4T1 breast tumours, prevents metastasis and recurrence, and prolongs survival without systemic side effects. Furthermore, it greatly enhances the effectiveness of PD-L1 antibody immunotherapy in the 4T1 late-stage lung metastasis and aggressive orthotopic Pan02 pancreatic tumour models. Our research may open pathways for developing stimuli-responsive pyroptosis inducers for precise cancer immunotherapy.

A Self-Priming Pyroptosis-Inducing Agent for Activating Anticancer Immunity

Pyroptosis, a form of programmed cell death mediated by the gasdermin family, has emerged as a promising strategy for inducing anti-tumor immunity. However, efficiently inducing pyroptosis in tumor cells remains a significant challenge due to the limited activation of key mediators like caspases in tumor tissues. Herein, a self-priming pyroptosis-inducing agent (MnNZ@OMV) is developed by integrating outer membrane vesicles (OMVs) with manganese dioxide nanozymes (MnNZ) to trigger pyroptosis in tumor cells. OMVs, derived from Escherichia coli, are coated onto spiny MnNZ to prepare MnNZ@OMV. Once internalized by tumor cells, MnNZ@OMV responds to elevated intracellular glutathione (GSH) levels, releasing Mn2⁺ and OMV components. This leads to GSH depletion and Mn2⁺-catalyzed reactive oxygen species generation, which triggers NF-κB translocation and prime caspase-11 expression. Subsequently, lipopolysaccharides from OMVs activate caspase-11, resulting in GSDMD cleavage and pyroptosis induction. MnNZ@OMV significantly induces tumor pyroptosis in vivo, promoting dendritic cell maturation and CD8⁺ T cell activation, leading to robust anti-tumor effects. Collectively, this study presents a novel self-priming approach for inducing tumor cell pyroptosis through the noncanonical caspase-11/GSDMD pathway, offering a promising avenue for future cancer immunotherapy.

Long non-coding RNA ZFAS1 promotes ferroptosis by regulating the miR-185-5p/SLC25A28 axis in clear cell renal cell carcinoma

Ferroptosis is a novel, iron-dependent regulated cell death mode. The biochemical features of ferroptosis include iron accumulation, lipid peroxidation, inhibition of glutathione peroxidase 4 (GPX4) and antioxidant glutathione (GSH) decrease through inhibition of the system xc- transporter. Zinc finger NFX1 type-containing 1 (ZNFX1) antisense RNA 1 (ZFAS1) is a long non-coding RNA that has been identified as an oncogene in various types of cancers. However, its regulatory role and molecular mechanisms in clear cell renal cell carcinoma (ccRCC) ferroptosis remain unclear. In this study, the ferroptosis inducers (FINS) (erastin and RSL3) were found to increase ZFAS1 expression through the facilitation of SP1 binding to the ZFAS1 promoter. ZFAS1 increased mRNA and protein levels of solute carrier family 25 member 28 (SLC25A28) via functioning as a miR-185-5p sponge. Overexpressed SLC25A28 increased the production of ROS and caused a decrease in NADPH and GSH in cells treated with FINS. In addition, overexpression of ZFAS1 enhanced ferroptosis both in vitro and in vivo. Altogether, this study demonstrates that ZFAS1 is a crucial element of ferroptosis in ccRCC, as it is responsible for the regulation of miR-185-5p and SLC25A28. Introducing ferroptosis could be a beneficial approach to treat ccRCC patients with high ZFAS1 levels.

A Spatially Distributed Microneedle System for Bioorthogonal T Cell-Guided Cancer Therapy

Chimeric antigen receptor (CAR)-T cell therapy represents a promising strategy for cancer treatment. However, the diversity of solid tumor antigens and the poor infiltration of CAR-T cells significantly hinder the efficacy of CAR-T therapies against tumors. Here, a spatially distributed microneedle system (SDMNS) is developed that leverages bioorthogonal reactions to activate and guide endogenous T cells to tumors for effective destruction. The SDMNS consists of two dissolving microneedles, each loaded with complementary bioorthogonal groups and applied separately to lymph nodes and tumor sites. One microneedle loaded with two dibenzocyclooctyne (DBCO)-modified antibodies activates T cells and labels them with bioorthogonal groups in lymph nodes. The other microneedle, containing N-azidoacetylmannosamine-tetraacylated (Ac4ManNAz) for glycometabolic labeling of tumor cells, and the T cell chemotactic factor IP10, is applied directly to the tumor site. The in vivo studies demonstrate that SDMNS effectively directs the migration and infiltration of endogenous activated T cells into the tumors. Through a bioorthogonal click reaction, DBCO-modified T cells conjugate with azide (N3)-modified tumor cells, eliciting robust antitumor immune responses and durable immune memory. The SDMNS offers a novel strategy to overcomes tumor heterogeneity by facilitating the directed migration of endogenous T cells.

Accelerating Tumor Immunotherapy Through a Synergistic Strategy of Increasing Throttle and Relaxing Brake

Tumor immunotherapy has been widely used clinically, but it is still hindered by weak antitumor immunity and immunosuppressive tumor microenvironment (TME). Here, a kind of simple disodium hydrogen phosphate nanoparticle (Na2HPO4 NP) is prepared to "accelerate" tumor immunotherapy by "increasing throttle" and "relaxing brake" simultaneously. The obtained Na2HPO4 NPs release a large amount of Na+ and HPO4 2- ions within tumor cells, thereby activating the caspase 1/GSDMD-mediated pyroptosis pathway to achieve immune activation. Meanwhile, alkalescent Na2HPO4 NPs can further consume lactic acid through acid-base neutralization, and regulate adenosine (Ado) metabolism via nanomaterial-induced biocatalytic process to relieve two-tier immunosuppression. Collectively, Na2HPO4 NPs effectively activate the antitumor immune process in vivo, and dramatically inhibit primary and distal tumor growth. This work will provide unique inspiration and strategy for the regulation of both positive and negative directions in immunotherapy.

Fine-tuning phenoxy silyl scaffolds for the development of glutathione-responsive prodrugs and antibody-drug conjugates

Silyl ether is particularly attractive for application in drug development for its easy preparation, non-toxicity and remarkable biocompatibility. Earlier studies relied on the use of intracellular acidic conditions to induce the cleavage of alkoxy silyl ethers. However, acidic conditions are not suitable to trigger the release of phenoxy silyl ethers, since they are more stable under acidic conditions compared with neutral conditions. We explored the vulnerability of the phenoxy silyl ether towards biological nucleophilic reagents and found that glutathione (GSH) could effectively and selectively induce the cleavage of phenoxy silyl ether. We also demonstrated that the rate of cleavage was controllable by adjusting the substituents on the phenyl ring. Phenoxy silyl ether-based prodrugs and antibody-drug conjugates (ADCs) were designed and synthesized, which could be effectively activated in cells with high GSH levels and there was an obvious therapeutic window between cells with different GSH levels.

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.

Hyaluronic acid-mediated targeted nano-modulators for activation of pyroptosis for cancer therapy through multichannel regulation of Ca2+ overload

Calcium-based nanomaterials-mediated Ca2+ overload-induced pyroptosis and its application in tumor therapy have received considerable attention. However, the calcium buffering capacity of tumor cells can maintain mitochondrial calcium homeostasis, so it is important to effectively disrupt this homeostasis to activate pyroptosis. Here, a nano-modulator CUR@CaCO3-PArg@HA (CCAH) was developed to regulate calcium overload in multiple channels and activate pyroptosis. Hyaluronic acid (HA)-coated nano-modulators achieve tumor targeting, and under the weakly acidic conditions of the tumor microenvironment (TME), CaCO3 nanoparticles rapidly release curcumin (CUR), inhibit the outflow of intracellular Ca2+, and release exogenous Ca2+. Meanwhile, poly-L-arginine (PArg) reacts with reactive oxygen species (ROS) generated by mitochondrial imbalance, releasing nitric oxide (NO) and stimulating the endoplasmic reticulum to release endogenous Ca2+. The combined action of endogenous and exogenous Ca2+ effectively activates caspase-1, which cleaves gasdermin-D (GSDMD) to produce the active N-terminus (GSDMD-N), effectively activating pyroptosis. Notably, the generated ROS and NO can also generate more oxidizing ONOO-, further exacerbating the imbalance in mitochondrial homeostasis. This work demonstrates that simultaneous modulation of exogenous and endogenous Ca2+ can disrupt mitochondrial Ca2+ homeostasis and effectively activate pyroptosis to treat tumors, which is expected to promote the progression of cancer treatment in the future.

A Pyroptosis Radiosensitizer Facilitates Hypoxic Tumor Necrosis

Hypoxia-related tumor radioresistance markedly impairs the efficacy of radiotherapy. Herein, a targeted radiosensitization strategy is introduced, leveraging the upregulation of gasdermin C (GSDMC) in hypoxic tumor cells, aiming to induce pyroptosis through the application of a cobalt-containing polyoxometalate-based radiosensitizer. This novel radiosensitizer is designed for the precisely controlled release of cobalt ions upon X-ray irradiation, thereby activating caspase-8 and prompting the cleavage of GSDMC. This sequence of events selectively triggers pyroptosis in hypoxic tumor cells, directly addressing radioresistance. The ensuing results highlight the enhanced radiotherapy efficacy and tumor necrosis both in vitro and in vivo models. Overall, the findings confirm the effectiveness of this strategy targeting high GSDMC expression in hypoxic tumors to induce pyroptosis for precise radiotherapy. Such findings encourage further exploration of hypoxia-driven pyroptosis to improve cancer treatment outcomes.

5-FU@HFn combined with decitabine induces pyroptosis and enhances antitumor immunotherapy for chronic myeloid leukemia

BACKGROUND

Tyrosine kinase inhibitors (TKIs) constitute the primary treatment for chronic myeloid leukemia (CML). However, resistance to TKIs often leads to treatment failure. Pyroptosis, a form of programmed cell death, has emerged as a promising strategy in cancer therapy due to its ability to eliminate tumor cells while stimulating antitumor immunity. Low-dose decitabine (DAC) has been shown to reverse methylation-induced silencing of the pyroptosis-related gene gasdermin E (GSDME) in some tumor cells, offering a potential new therapeutic option for CML. Herein, we propose a combination therapy using 5-fluorouracil (5-FU), a broad-spectrum chemotherapeutic agent, and low-dose DAC to induce pyroptosis in CML cells via the caspase-3/GSDME pathway. However, the nonspecific targeting of 5-FU diminishes its pyroptosis efficacy and causes off-target toxicity, highlighting the need for a targeted drug delivery system.

RESULTS

In this study, we developed 5-FU@HFn nanoparticles (NPs) by loading 5-FU into the recombinant human heavy chain ferritin (HFn) nanocage through a high-temperature via the drug channels on the protein cage. The loading efficiency was approximately 50.62 ± 1.17 µg of 5-FU per mg of HFn. 5-FU@HFn NPs selectively targeted CML cells through CD71-mediated uptake, significantly enhancing the therapeutic effects of 5-FU. When combined with DAC, 5-FU@HFn NPs effectively activated pyroptosis via the caspase-3/GSDME pathway in both TKI-sensitive and TKI-resistant CML cells. In a CML mouse model, this combination therapy significantly suppressed tumorigenesis and triggered a robust antitumor immune response, facilitating the clearance of leukemic cells. Furthermore, the 5-FU@HFn NPs exhibited excellent in vivo safety.

CONCLUSIONS

The innovative therapeutic strategy, combining 5-FU@HFn nanoparticles with low-dose DAC, effectively induces caspase-3/GSDME-mediated pyroptosis and activates antitumor immunity for CML. This approach offers a potential alternative for patients resistant or intolerant to TKIs.

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.

Cell death in tumor microenvironment: an insight for exploiting novel therapeutic approaches

Cell death is critical in tumor biology. The common cancer therapies can cause cell death and alleviate tumor, while the cancer cells can develop a resistance to cell death and survive from the therapies. Thus, not only observing the alternative mechanisms of tumor cells resistant to cell death, but also understanding the intricate dynamics of cell death processes within the tumor microenvironment (TME), are essential for tailoring effective therapeutic strategies. High-throughput sequencing technologies have revolutionized cancer research by enabling comprehensive molecular profiling. Recent advances in single cell sequencing have unraveled the heterogeneity of TME components, shedding light on their complex interactions. In this review, we explored the interplay between cell death signaling and the TME, summarised the potential drugs inducing cell death in pre-clinical stage, reviewed some studies applying next-generation sequencing technologies in cancer death research, and discussed the future utilization of updated sequencing platforms in screening novel treatment methods targeted cell death. In conclusion, leveraging multi-omics technologies to dissect cell death signaling in the context of the TME holds great promise for advancing cancer research and therapy development.

Neuropilin-1-target self-assembled peptide nanoparticles contribute to tumor treatment by inducing pyroptosis

BACKGROUND

Expression of the Neuropilin-1 (NRP1) is reported in malignant cells of multiple human tumor types represented as a tumor marker. Targeting NRP1 with a peptide, CK3, is used for tumor molecular imaging, raising the question of the therapeutic potential of CK2, a peptide with a CK3 backbone which enhanced targeting and tumor enrichment properties.

METHODS

The tumor targeting and enrichment capacity of CK2 was detected by IncuCyte, flow cytometry and animal living imaging. To enhance its therapeutic efficacy, we developed a self-assembling peptide nanoparticles Fmoc-Gffy-AP-CK2, incorporating a peptide protective domain (Fmoc), a self-assemble domain (Gffy) and an anti-tumor peptide (AP). In vitro cellular assays and in vivo tumor-xenograft experiments were conducted to evaluate the anti-tumor effect of Fmoc-Gffy-AP-CK2.

RESULTS

While CK3 peptide specifically targets NRP1 in vitro and in vivo, CK2 markedly achieves stronger binding with NRP1 and higher tumor accumulation. Fmoc-Gffy-AP-CK2 exhibits a potent NRP1-dependent cytotoxic effect in vitro and in vivo. Mechanically, Fmoc-Gffy-AP-CK2 triggered caspase3/gasdermin E (GSDME)-mediated pyroptosis. Fmoc-Gffy-AP-CK2 also promotes the response rate of PD-1 checkpoint blockade.

CONCLUSIONS

CK2, When combined with Fmoc-Gffy-AP domain, Demonstrated high anti-tumor efficacy, Providing a novel strategy for tumor treatment.

Targeting GOLPH3L improves glioblastoma radiotherapy by regulating STING-NLRP3-mediated tumor immune microenvironment reprogramming

Radiotherapy (RT) has been the standard-of-care treatment for patients with glioblastoma (GBM); however, the clinical effectiveness is hindered by therapeutic resistance. Here, we demonstrated that the tumor immune microenvironment (TIME) exhibited immunosuppressive properties and high expression of Golgi phosphoprotein 3 like (GOLPH3L) in RT-resistant GBM. Our study showed that GOLPH3L interacted with stimulator of interferon genes (STING) at the aspartic acid residue 184 in Golgi after RT, leading to coat protein complex II-mediated retrograde transport of STING from Golgi to endoplasmic reticulum. This suppressed the STING-NOD-like receptor thermal protein domain associated protein 3 (NLRP3)-mediated pyroptosis, resulting in suppressive TIME, driving GBM resistance to RT. Genetic GOLPH3L ablation in RT-resistant GBM cells augmented antitumor immunity and overcame tumor resistance to RT. Moreover, we have identified a small molecular inhibitor of GOLPH3L, vitamin B5 calcium (VB5), which improved the therapeutic efficacy of RT and immune checkpoint blockade by inducing a robust antitumor immune response in mouse models. Clinically, patients with GBM treated with VB5 exhibited improved responses to RT. Thus, reprogramming the TIME by targeting GOLPH3L may offer a potential opportunity to improve RT in GBM.

Hydrotalcites-Induced Pyroptosis Combined with Toll-Like Receptor Activation Elicited Dual Stimulation of Innate and Adaptive Immunity

Increasing evidence illustrates the significance of promoting tumor immunogenicity and an efficient immune response in immunotherapy, but the immunosuppressive tumor microenvironment (TME) remains an obstacle. Herein, AlZn hydrotalcite (AZOH) was synthesized as a pyroptosis inducer and further loaded with R848 to formulate R@AZOH. R@AZOH efficiently triggered CT26 cell pyroptosis through Zn2+ overload-evoked mitochondrial dysfunction and its downstream caspase-1/GSDMD pathway, resulting in the release of inflammatory cytokines, membrane fracture, and immunogenic cell death (ICD). Moreover, R@AZOH served as antigen traps to facilitate antigen presentation, thereby cooperating with TLR activation to dually stimulate dendritic cells (DCs). The combination of R@AZOH rapidly initiated innate immunity and prolonged the adaptive immune response, resulting in the suppression of tumor growth, immune cell activation and a "hot" tumor niche. The potent antitumor immunity was further enhanced by combination with an immune checkpoint inhibitor (αCTLA-4), which inhibited both primary and distant tumors, as well as systemic immune activation. Astonishingly, we also explored the potential application of R@AZOH as a tumor vaccine adjuvant and demonstrated its ability to elicit immunological memory to prevent tumor growth in an orthotopic melanoma model. Overall, our work emphasized the potential application of combining pyroptosis and TLR activation to stimulate both innate and adaptive immunity to overcome the immunosuppressive TME and presented a good adjuvant candidate.

Engineered Metal-Organic Framework with Stereotactic Anchoring and Spatial Separation of Porphyrins for Amplified Ultrasound-Mediated Pyroptosis and Cancer Immunotherapy

Ultrasound-mediated reactive oxygen species (ROS) generation is pivotal in specifically inducing pyroptosis of tumor cells. However, the effectiveness of pyroptosis is generally hindered by the constraints of ROS generation efficiency. Herein, a new porphyrin-based metal-organic framework (Fe(TCPP)-MOF) was rationally designed via an innovative dual-solvent strategy to amplify ROS generation for ultrasound-controlled pyroptosis. The crystal structure of Fe(TCPP)-MOF was elucidated by continuous rotation electron diffraction technique, revealing its regular and rigid conformation. The porphyrin molecules were precisely oriented and firmly confined within the scaffold, effectively restricting intramolecular motion. The ample distance of 6.8 Å between two porphyrin molecules, combined with the interaction region indicator visualization, confirmed the absence of π-π stacking interactions in the Fe(TCPP)-MOF framework, thereby avoiding the aggregation-caused quenching effect. Furthermore, the permanent porosity and expansive surface area of Fe(TCPP)-MOF enhanced its interaction with oxygen. These ingenious structural features endowed Fe(TCPP)-MOF with a unique ability to generate a large amount of singlet oxygen under ultrasound activation. Meanwhile, the impetus of ultrasound also accelerated the rate of the Fenton reaction catalyzed by iron ions, significantly boosting the generation of hydroxyl radicals. Benefiting from the dual amplification of ROS, Fe(TCPP)-MOF could efficiently induce tumor cells pyroptosis under ultrasound stimulation, thereby intensifying the potency of cancer immunotherapy.

A One Stone Three Birds Paradigm of Photon-Driven Pyroptosis Dye for Amplifying Tumor Immunotherapy

Activating the pyroptosis pathway of tumor cells by photodynamic therapy (PDT) for immunogenic cell death (ICD) is considered a valid strategy in pursuit of antitumor immunotherapy, but it remains a huge challenge due to the lack of reliable design guidelines. Moreover, it is often overlooked that conventional PDT can exacerbate the development of tumor immunosuppressive microenvironment, which is apparently unfavorable to clinical immunotherapy. The endoplasmic reticulum's (ER) pivotal role in cellular homeostasis and its emerging link to pyroptosis have galvanized interest in ER-centric imaging and therapeutics. Herein, using the targeted group-assisted strategy (TAGS), an intriguing cyclooxygenase-2-targeted photodynamic conjugate, Indo-Cy, strategically created, which exploits the enzyme's overabundance in the tumoral ER, especially under proinflammatory hypoxic conditions. This conjugate, with its highly precise ER imaging, embodies a trifunctional strategy: i) innovating an electron transfer mechanism, converting the hemicyanine moiety into an oxygen-independent type I photosensitizer, thereby navigating around the hypoxia constraints of traditional PDT; ii) executing precise ER-targeted PDT, amplifying caspase-1/GSDMD-mediated pyroptosis for ICD; 3) attenuating immunosuppressive pathways by inhibiting cyclooxygenase-2 downstream factors, including HIF-1α, PGE2, and VEGF. Indo-Cy's multimodal approach potently induces in vivo tumor pyroptosis and bolsters antitumor immunity, underscoring cyclooxygenase-2-targeted dyes' potential as a versatile oncotherapeutics.

Chromosome Missegregation Triggers Tumor Cell Pyroptosis and Enhances Anti-Tumor Immunotherapy in Colorectal Cancer

Immune checkpoint inhibitor (ICI) therapy is a promising anti-tumor therapeutic strategy; however, its efficacy in solid tumors is limited. Chromosome missegregation is common in various solid tumors; however, its role in tumor progression remains poorly understood, and its correlation with ICI is yet to be explored. Here, it is found that increased chromosome missegregation promotes tumor immune microenvironment, and eventually immunotherapeutic efficacy, by triggering pyroptosis. yin yang 2 (YY2) is identified as a mitotic checkpoint regulator, which promotes chromosome missegregation by upregulating BUB1B transcription. Increased chromosome missegregation promoted the formation of micronuclei and release of double-stranded DNA (dsDNA) into the cytosol, triggering an AIM2-mediated cytosolic dsDNA response. The subsequent pyroptosis strengthened the tumor immune microenvironment, thereby enhancing immunoinfiltration and cytotoxicity of CD8+ T cells, while preventing their exhaustion. Finally, through in vitro and in vivo experiments, it is demonstrated that combining YY2 overexpression-induced chromosome missegregation/cytosolic dsDNA response and PD-1 inhibitor significantly enhanced the efficacy of ICI immunotherapy in microsatellite instable and microsatellite stable colorectal cancer cells. Together, these findings provide new insights on the role of chromosome missegregation in triggering cytosolic dsDNA response-mediated pyroptosis and modulating the tumor immune microenvironment, suggesting a novel strategy for improving ICI therapeutic efficacy in colorectal cancer.

Creating Single Atomic Coordination for Hypoxia-Resistant Pyroptosis Nano-Inducer to Boost Anti-Tumor Immunotherapy

General synthesis and mechanical understanding of type I nano-photosensitizers are of great importance for hypoxia-resistant pyroptosis inducers. Herein, a simple solvothermal treatment is developed to convert non-photosensitive small molecules (hemin) into uniform carbon nanodots (HNCDs) with strong type I photodynamic activity and red fluorescence emission. These HNCDs inherit the single atomic Fe-N4 center of hemin while creating sp2-hybridized carbon surroundings, which synergistically modulated the energy level and electron transfer for converting the type II photodynamic process to type I. After encapsulating HNCDs with bovine serum albumin (BSA) to facilitate in vivo applications, the resulting BSA nanoparticles (HB) can image tumors and significantly induce the pyroptosis of tumor cells even under an extremely hypoxic environment (2% O2). This evokes a strong antitumor immune response, effectively restraining tumor growth and lung metastasis in triple-negative breast cancer mice, with good biocompatibility. This work introduces an applicable pyroptosis nano-inducer to combat hypoxic tumors and highlights the regulation of Fe-N4 centers to develop hypoxia-resistant type I nano-photosensitizers for cancer treatment.

Bioorthogonal Reaction of β-Chloroacroleins with meta-Aminothiophenol to Develop Near-Infrared Fluorogenic Probes for Simultaneous Two-color Imaging

Highly fluorogenic probe based bioorthogonal chemistry has become a promising tool in biomedical applications. However, the majority of fluorogenic probes are designed by introducing a bioorthogonal partner as a fluorescence quencher into classical fluorophores, and these probes exhibit a deteriorating fluorogenicity as the emission wavelength shifts toward the near-infrared (NIR) region, greatly limiting their applications in vivo. Herein, we report a novel fluorogenic bioorthogonal reaction involving β-chloroacroleins (β-CAs) and meta-aminothiophenol (m-AT1), whose fluorescence increases more than 500-fold upon in situ generating fluorophores. β-CAs are stable under physiological conditions and react rapidly (β-CA9, k2 = 2.2 × 102 M-1 s-1, in H2O) and chemoselectively with m-AT1 in the presence of biological nucleophiles, and delightfully, the reaction proceeds swiftly even under solvent-free conditions. Furthermore, manipulating the conjugate length of β-CAs enables the emission wavelength of the probes to be fine-tuned from 627 to 778 nm. These probes allow the simultaneous labeling of multiple cellular organelles without washing steps, and two-color tumor visualization is achieved in living mice. We believe this study not only provides new insights for the development of NIR fluorogenic probes with superior turn-on behaviors but also presents a promising fluorogenic bioorthogonal reaction CA-AT with widespread potential applications in biomedical research.

Targeting pyroptosis reverses KIAA1199-mediated immunotherapy resistance in colorectal cancer

BACKGROUND

Despite advancements in treatment modalities, several patients with colorectal cancer (CRC) remain unresponsive to immune checkpoint inhibitor therapy. Pyroptosis, an inflammatory programmed cell death process, holds substantial promise for tumor immunotherapy. In this study, we explored the use of pyroptosis to overcome immunotherapy resistance in CRC.

METHODS

We used a pyroptosis-related gene panel to construct an immunotherapy efficacy evaluation model and validated its performance by immunohistochemical staining of CRC patient samples. Pyroptosis and its underlying mechanisms were examined both in vitro and in vivo using PCR, western blotting, lactate dehydrogenase release assay, ELISA, co-immunoprecipitation, immunohistochemistry, fluorescence cell assays, microscopic imaging, flow cytometry analysis and bioinformatics approaches.

RESULTS

We established a model to define high or low levels of pyroptosis in CRC, revealed that low pyroptosis led to immunotherapy resistance, and identified KIAA1199 as a characteristic protein of low pyroptosis CRC. We further demonstrated that KIAA1199 contributes to low pyroptosis, resulting in resistance to immunotherapy. Mechanistically, KIAA1199 bound to and stabilized DNA methyltransferase-1 (DNMT1), thereby inhibiting GSDME-mediated pyroptosis. Importantly, our study highlighted that decitabine reversed KIAA1199-mediated immunotherapy resistance by enhancing pyroptosis to restore IL-1B release and CD8+ T cell infiltration.

CONCLUSIONS

We found a critical role of KIAA1199 in promoting immunotherapy resistance by suppressing pyroptosis via the DNMT1/GSDME pathway in CRC. Decitabine has emerged as a promising therapeutic agent for reversing KIAA1199-mediated immunotherapy resistance by enhancing pyroptosis. Our findings provide valuable insights for enhancing the efficacy of immunotherapy in patients with CRC who exhibit resistance to conventional immunotherapy approaches.