Disulfidptosis is a form of regulated cell death triggered by disulfide stress resulting from glucose starvation. The capacity to evade disulfidptosis is crucial for tumour cells to withstand glucose-limited environments. Here we demonstrate that OGDH, a rate-limiting enzyme in citric acid cycle, is critical for conferring resistance to disulfidptosis. High expression of HSPA9 in melanoma protects OGDH from glucose deprivation-induced oxidative inactivation, thereby ensuring OGDH-generated succinyl-CoA for METTL3 succinylation. Succinylated METTL3 recognizes m6A modification on NRF2 mRNA to license NRF2 translation, TrxR1 expression and subsequent evasion of disulfidptosis. Combined suppression of HSPA9 and glucose uptake inhibits melanoma growth in mouse models. In patients with melanoma, expressions of HSPA9 and OGDH negatively correlate with the disulfidptosis signature and are associated with an unfavourable clinical prognosis. Therefore, our findings not only highlight the dependence of melanoma cells on the HSPA9-OGDH-METTL3-NRF2 axis for disulfidptosis evasion, but also propose a combined intervention strategy for melanoma therapy.

Helicobacter pylori (H. pylori) infection is the primary driver in gastric cancer (GC) development, but the dynamic changes of the gastric mucosal microenvironment during H. pylori-associated GC progression remains elusive. Here, we perform single-cell RNA sequencing (scRNA-seq) on 21 gastric mucosae collected from four typical stages of GC progression under H. pylori infection. Our scRNA-seq analysis delineates the cellular landscape, dissects the dynamic alterations, and characterizes distinct immune cell populations. Notably, H. pylori-associated activated mast cells upregulate CD38 and COX2 expression, leading to increased secretion of adenosine and prostaglandin E2 (PGE2). PGE2 enhances adenosine receptor expression in CD8+ T cells, thereby suppressing their cytotoxicity via adenosine signaling. Cellular interactions are more complex at the GC stage than in the premalignant lesions. Collectively, our study offers a comprehensive insight into the evolving gastric mucosal microenvironment and validates the pro-tumor role of activated mast cells under H. pylori infection.

Recently, a growing number of novel types of regulated cell death have been reported, including pyroptosis, necroptosis, and ferroptosis, among others. These types of cell death play crucial roles in a wide array of physiological functions such as metabolism, tissue injury and repair, chronic disease progression, and immune protection. However, specifically targeting cell death pathways for therapeutic purposes remains a challenge due to the unresolved complexities in pharmacological intervention. Nuclear receptor superfamily members, a class of prominent targets in drug discovery, are involved in diverse physiological and pathological processes. Investigating the regulatory functions between nuclear receptors and cell death is essential for understanding their roles in cell death and developing novel treatment methods for cell death-related diseases. This review discusses the mechanisms and functional significance of nuclear receptors in cell death across various physiological and pathological conditions, summarizes current ligands and compounds that facilitate targeting nuclear receptors to modulate cell death, and aims to promote the development of novel pharmacological strategies.

Hepatocellular carcinoma (HCC) typically emerges in a fibrotic premalignant liver milieu, and hepatic stellate cells (HSCs) represent the predominant cell subtype implicated in hepatic fibrosis. The crosstalk between HCC cells and HSCs has been demonstrated to affect HCC progression. Our prior research revealed that the activation of HSCs in hepatic fibrosis is accompanied with secretion of hexokinase 1 (HK1), an enzyme catalysing the initial step of glycolysis, through large extracellular vesicles (lEVs), which are selectively internalised by HCC cells to promote their glucose metabolism and tumour progression. In the present study, we found that the boosted glucose metabolism in HCC cells can reciprocally activate HSCs, thereby facilitating the formation of a pro-tumourigenic fibrotic microenvironment. Specifically, HSCs-transmitted lEV HK1 was identified as a key factor that markedly enhances the ability of HCC cells to activate HSCs. Mechanistically, HK1 accelerates the metabolic flux of hexosamine biosynthesis pathway, thereby promoting N-glycosylation of pro-transforming growth factor-β (TGF-β)1 and facilitating its secretion from HCC cells, which subsequently activates HSCs. This HCC cell-induced HSC activation is accompanied by increased secretion of lEV HK1 from HSCs, establishing a feedforward loop between HCC cells and HSCs. Furthermore, this intercellular communication was confirmed to exacerbate HCC progression in several mouse models, and disrupting this communication significantly inhibited HCC progression. Together, this study highlights that targeting the disruption of this feedforward loop may represent a promising and effective therapeutic strategy for HCC treatment.

Integral membrane protein 2B (ITM2B), a transmembrane protein, frequently undergoes cleavage. The physiological functions of ITM2B are primarily studied in the context of neurological disorders, but their roles in cancers are largely overlooked. Here, it is demonstrated that in renal cell carcinoma (RCC) cells, N-terminal truncation of ITM2B facilitates migrasome swelling through the recruitment of TSPAN4 and promotes migrasome formation. Moreover, ITM2B truncation acts as a carrier, sorting active caspase-7 into migrasomes for migracytosis. The active caspase-7-enriched migrasomes are then taken up by macrophages, leading to caspase-7-induced IL-6 secretion from macrophages, which eventually aggravates RCC growth through a feedback mechanism. Physiologically, hyperuricemia enhances ITM2B cleavage to aggravate RCC growth. Clinically, RCC tissues tend to produce ITM2B truncations compared with corresponding para-carcinoma tissues. Moreover, compared with the urine from normal volunteers, that from RCC patients contains higher levels of ITM2B truncation-enriched migrasomes. This study not only highlights novel functions of ITM2B truncation in migrasome formation and active caspase-7 migracytosis but also elucidates the role of hyperuricemia in RCC progression via regulation of the ITM2B truncation-migrasome axis.

Pyroptosis plays a crucial role in physiological and pathological processes. As melanoma cells are resistant to apoptosis but express gasdermin proteins, it is appealing to counter melanoma with the induction of gasdermin-executed pyroptosis. GSDMC, initially cloned from metastatic melanoma cells, has been demonstrated as a potential executioner of pyroptosis. However, no lead compounds that trigger GSDMC-mediated pyroptosis have been reported, which limits the in-depth investigation of GSDMC functions. Here, we discovered a chemical compound, dodecyl 1H-benzo[d]imidazole-5-carboxylate (DdBIC), that targeted the nuclear receptor Nur77 to induce pyroptosis through cleaving GSDMC by granzyme B in melanoma cells. Upon DdBIC binding, Nur77 was translocated to the mitochondria to activate the hemoprotein SDHA to overconsume succinyl-CoA, subsequently disrupting the homeostasis of heme in the SDH complex and resulting in electron leakage to induce mito-ROS production. This mito-ROS signal was sensed by the mitochondrial protease OMA1 via oxidation, which led to downstream OPA1 cleavage and subsequent released into the cytoplasm. Cytosolic OPA1 activated PERK to induce the integrated stress response (ISR), which further activated granzyme B to cleave GSDMC, culminating in the induction of pyroptosis. Together, this study elucidates a signal cascade from Nur77-impaired homeostasis of heme metabolism to PERK-mediated ISR activation, and reveals a novel paradigm, by which granzyme B, rather than caspases, cleaves GSDMC for pyroptotic induction and provides a new strategy for the therapeutic treatment of melanoma by lead compound DdBIC.

Protein kinase AKT plays a broad role in promoting energy production in nutrient-rich environments. However, its roles under metabolic stress remain elusive. Herein, we demonstrate a dual mechanism for AKT activation during glucose deprivation. On one hand, glucose deprivation leads to increased levels of ADP and NADP+, which directly bind to spleen tyrosine kinase (SYK) and induce a conformational alteration of SYK, resulting in self-activation. The activated SYK further triggers PI3K-dependent activation of AKT. On the other hand, elevated ROS upon glucose deprivation promotes oxidative dimerization of PDK1, thereby facilitating the recognition and activation of AKT. In melanoma cells, AKT plays a critical role in elevating ROS levels and inducing cell death during glucose deprivation. Overall, this study not only establishes a novel connection between energy insufficiency and AKT activation via a dual mechanism but also provides insights into the role of AKT in sensitizing cells to metabolic stress.

The cyclic GMP-AMP synthase (cGAS)/stimulator of IFN genes (STING) pathway is intimately associated with antitumoral immunity; however, the direct involvement of this pathway in tumor cell demise remains elusive. Here, we identified a compound, dodecyl 6-hydroxy-2-naphthoate (DHN), that induces pyroptosis in melanoma cells by activating noncanonical cGAS/STING signaling. DHN targets mitochondrial protein cyclophilin D (CypD) to induce the release of mitochondrial DNA, leading to cGAS activation and cyclic GMP-AMP (cGAMP) generation. Meanwhile, DHN-caused intracellular acidification induces protein kinase R-like endoplasmic reticulum kinase (PERK) activation, which promotes STING phosphorylation and polymerization in the presence of cGAMP, thereby facilitating the aggregation of STING in the ER, which serves as a platform to recruit Fas-associated via death domain (FADD) and caspase-8, leading to caspase-8 activation and subsequent gasdermin E cleavage, which ultimately results in pyroptosis of tumor cells and tumor regression in mouse models. The occurrence of this noncanonical cGAS/STING pathway-associated pyroptosis is also observed when both cGAS is activated and intracellular pH declines. Collectively, our findings reveal a pathway that links noncanonical cGAS/STING signaling to gasdermin E-mediated pyroptosis, thereby offering valuable insights for tumor therapy.

Gasdermin (GSDM) family proteins, known as the executors of pyroptosis, undergo protease-mediated cleavage before inducing pyroptosis. We here discovered a form of pyroptosis mediated by full-length (FL) GSDME without proteolytic cleavage. Intense ultraviolet-C irradiation-triggered DNA damage activates nuclear PARP1, leading to extensive formation of poly(ADP-ribose) (PAR) polymers. These PAR polymers are released to the cytoplasm, where they activate PARP5 to facilitate GSDME PARylation, resulting in a conformational change in GSDME that relieves autoinhibition. Moreover, ultraviolet-C irradiation promotes cytochrome c-catalysed cardiolipin peroxidation to elevate lipid reactive oxygen species, which is then sensed by PARylated GSDME, leading to oxidative oligomerization and plasma membrane targeting of FL-GSDME for perforation, eventually inducing pyroptosis. Reagents that concurrently stimulate PARylation and oxidation of FL-GSDME, synergistically promoting pyroptotic cell death. Overall, the present findings elucidate an unreported mechanism underlying the cleavage-independent function of GSDME in executing cell death, further enriching the paradigms and understanding of FL-GSDME-mediated pyroptosis. Zhou, Jiang, Dai et al report that upon ultraviolet-C radiation, full-length GSDME can induce pyroptosis without cleavage, likely due to conformational change and oxidative oligomerization after increased PARylation and mitochondrial lipid ROS levels.

Supplementary Materials and Methods from A Unique Pharmacophore for Activation of the Nuclear Orphan Receptor Nur77 In vivo and In vitro

Pyroptosis is a type of regulated cell death executed by gasdermin family members. However, how gasdermin-mediated pyroptosis is negatively regulated remains unclear. Here, we demonstrate that mannose, a hexose, inhibits GSDME-mediated pyroptosis by activating AMP-activated protein kinase (AMPK). Mechanistically, mannose metabolism in the hexosamine biosynthetic pathway increases levels of the metabolite N -acetylglucosamine-6-phosphate (GlcNAc-6P), which binds AMPK to facilitate AMPK phosphorylation by LKB1. Activated AMPK then phosphorylates GSDME at Thr6, which leads to blockade of caspase-3-induced GSDME cleavage, thereby repressing pyroptosis. The regulatory role of AMPK-mediated GSDME phosphorylation was further confirmed in AMPK knockout and GSDME T6E or GSDME T6A knock-in mice. In mouse primary cancer models, mannose administration suppressed pyroptosis in small intestine and kidney to alleviate cisplatin- or oxaliplatin-induced tissue toxicity without impairing antitumor effects. The protective effect of mannose was also verified in a small group of patients with gastrointestinal cancer who received normal chemotherapy. Our study reveals a novel mechanism whereby mannose antagonizes GSDME-mediated pyroptosis through GlcNAc-6P-mediated activation of AMPK, and suggests the utility of mannose supplementation in alleviating chemotherapy-induced side effects in clinic applications.

Supplementary Figures 1-5 from A Unique Pharmacophore for Activation of the Nuclear Orphan Receptor Nur77 In vivo and In vitro

Supplementary Figures 1-5 from A Unique Pharmacophore for Activation of the Nuclear Orphan Receptor Nur77 <i>In vivo</i> and <i>In vitro</i>

Pulmonary fibrosis is a typical sequela of coronavirus disease 2019 (COVID-19), which is linked with a poor prognosis for COVID-19 patients. However, the underlying mechanism of pulmonary fibrosis induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is unclear. Here, we demonstrated that the nucleocapsid (N) protein of SARS-CoV-2 induced pulmonary fibrosis by activating pulmonary fibroblasts. N protein interacted with the transforming growth factor β receptor I (TβRI), to disrupt the interaction of TβRI-FK506 Binding Protein12 (FKBP12), which led to activation of TβRI to phosphorylate Smad3 and boost expression of pro-fibrotic genes and secretion of cytokines to promote pulmonary fibrosis. Furthermore, we identified a compound, RMY-205, that bound to Smad3 to disrupt TβRI-induced Smad3 activation. The therapeutic potential of RMY-205 was strengthened in mouse models of N protein-induced pulmonary fibrosis. This study highlights a signaling pathway of pulmonary fibrosis induced by N protein and demonstrates a novel therapeutic strategy for treating pulmonary fibrosis by a compound targeting Smad3.

Supplementary Materials and Methods from A Unique Pharmacophore for Activation of the Nuclear Orphan Receptor Nur77 <i>In vivo</i> and <i>In vitro</i>

Clinical information of patients with breast cancer.

Supplementary materials and methods and supplementary figure legends.

This file contains 7 supplementary figures supporting that Flightless-I blocks p62-mediated recognition of LC3 to impede selective autophagy and promote breast cancer progression.

Extracellular vesicles play crucial roles in intercellular communication in the tumor microenvironment. Here we demonstrate that in hepatic fibrosis, TGF-β stimulates the palmitoylation of hexokinase 1 (HK1) in hepatic stellate cells (HSCs), which facilitates the secretion of HK1 via large extracellular vesicles in a TSG101-dependent manner. The large extracellular vesicle HK1 is hijacked by hepatocellular carcinoma (HCC) cells, leading to accelerated glycolysis and HCC progression. In HSCs, the nuclear receptor Nur77 transcriptionally activates the expression of depalmitoylase ABHD17B to inhibit HK1 palmitoylation, consequently attenuating HK1 release. However, TGF-β-activated Akt functionally represses Nur77 by inducing Nur77 phosphorylation and degradation. We identify the small molecule PDNPA that binds Nur77 to generate steric hindrance to block Akt targeting, thereby disrupting Akt-mediated Nur77 degradation and preserving Nur77 inhibition of HK1 release. Together, this study demonstrates an overlooked function of HK1 in HCC upon its release from HSCs and highlights PDNPA as a candidate compound for inhibiting HCC progression.

Extracellular vesicles (EVs) have gained significant attention in recent decades as major mediators of intercellular communication that are involved in various essential physiological and pathological processes. They are secreted by almost all cell types and carry bioactive materials, such as proteins, lipids and nucleic acids, that can be transmitted from host cells to recipient cells, thereby eliciting phenotypic and functional alterations in the recipient cells. Recent evidence shows that EVs play essential roles in remodeling the tumor immune microenvironment (TIME). EVs derived from tumor cells and immune cells mediate mutual communication at proximal and distal sites, which determines tumor fate and antitumor therapeutic effectiveness. In this review, the current understanding of EVs and their roles in remodeling the TIME and modulating tumor-specific immunity are summarized. We mainly discuss the mutual regulation between tumor cells and tumor-infiltrating immune cells through the delivery of EVs in the TIME. We also describe the limitations of current studies and discuss directions for further research.