Stimulator Of Interferon Genes Signaling Pathway Research Articles

NS8593 inhibits sodium nitroprusside-induced chondrocyte apoptosis by mediating the STING signaling pathway

Articular cartilage damage and chondrocyte apoptosis are among the distinguishing features of osteoarthritis. (R)-N-(benzimidazol-2-yl)-1,2,3,4-tetrahydro-1-naphtylamine (NS8593) is a transient receptor potential cation channel subfamily M member 7 (TRPM7) channel inhibitor and was initially considered a potent inhibitor of small-conductance Ca2+-activated K+ channels(SK1-3 or KCa2.1–2.3 channels). Since SK is one of the targets for atrial fibrillation therapy, several studies have been conducted using NS8593 and it has been shown to be effective in improving atrial fibrillation in rats, dogs and horses. Recently, inhibition of TRPM7 has been reported to alleviate articular cartilage destruction. However, the role and mechanism of NS8593 on articular chondrocyte damage is unknown. The purpose of this study was to investigate the effect and mechanism of NS8593 on sodium nitroprusside (SNP)-induced chondrocyte apoptosis in vitro. The results showed that SNP decreased cell viability and induced chondrocyte apoptosis. NS8593 dose-dependently inhibited the SNP-induced decrease in cell viability and reduced chondrocyte apoptosis. In addition, SNP stimulation significantly increased the phosphorylation level of the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING), and NS8593 treatment partially reversed the alteration of STING phosphorylation level. Treatment with the STING inhibitor H-151 inhibited SNP-induced chondrocyte apoptosis. These results suggest that NS8593 may inhibit SNP-induced chondrocyte apoptosis by suppressing the STING signaling pathway.

Exogenous non-coding dsDNA-dependent trans-activation of phagocytes augments anti-tumor immunity

Stimulator of interferon genes (STING)-dependent signaling is requisite for effective anti-microbial and anti-tumor activity. STING signaling is commonly defective in cancer cells, which enables tumor cells to evade the immunosurveillance system. We evaluate here whether intrinsic STING signaling in such tumor cells could be reconstituted by creating recombinant herpes simplex viruses (rHSVs) that express components of the STING signaling pathway. We observe that rHSVs expressing STING and/or cGAS replicate inefficiently yet retain invivo anti-tumor activity, independent of oncolytic activity requisite on the trans-activation of extrinsic STING signaling in phagocytes by engulfed microbial dsDNA species. Accordingly, the invivo effects of virotherapy could be simulated by nanoparticles incorporating non-coding dsDNA species, which comparably elicit the trans-activation of phagocytes and augment the efficacy of established cancer treatments including checkpoint inhibition and radiation therapy. Our results help elucidate mechanisms of virotherapeutic anti-tumor activity as well as provide alternate strategies to treat cancer.

Neuronal STING activation in amyotrophic lateral sclerosis and frontotemporal dementia

The stimulator of interferon genes (STING) pathway has been implicated in neurodegenerative diseases, including Parkinson’s disease and amyotrophic lateral sclerosis (ALS). While prior studies have focused on STING within immune cells, little is known about STING within neurons. Here, we document neuronal activation of the STING pathway in human postmortem cortical and spinal motor neurons from individuals affected by familial or sporadic ALS. This process takes place selectively in the most vulnerable cortical and spinal motor neurons but not in neurons that are less affected by the disease. Concordant STING activation in layer V cortical motor neurons occurs in a mouse model of C9orf72 repeat-associated ALS and frontotemporal dementia (FTD). To establish that STING activation occurs in a neuron-autonomous manner, we demonstrate the integrity of the STING signaling pathway, including both upstream activators and downstream innate immune response effectors, in dissociated mouse cortical neurons and neurons derived from control human induced pluripotent stem cells (iPSCs). Human iPSC-derived neurons harboring different familial ALS-causing mutations exhibit increased STING signaling with DNA damage as a main driver. The elevated downstream inflammatory markers present in ALS iPSC-derived neurons can be suppressed with a STING inhibitor. Our results reveal an immunophenotype that consists of innate immune signaling driven by the STING pathway and occurs specifically within vulnerable neurons in ALS/FTD.

LicochalconeB inhibits cGAS-STING signaling pathway and prevents autoimmunity diseases

Cytosolic DNA activates the STING (stimulator of interferon genes) signaling pathway to trigger interferon and inflammatory responses that protect against microbial infections and cancer. However, Aicardi–Goutières syndrome (AGS) persistently activates the STING signaling pathway, which can lead to severe autoimmune diseases. We demonstrate herein that Licochalcone B (LicoB), the main component of traditional licorice, is an inhibitor of the STING signaling pathway. We observed that LicoB inhibited the activation of the STING signaling pathway in macrophages. Mechanically, LicoB affected the STING-TBK1-IRF3 signal axis and inhibited the activation of the STING downstream signaling pathway. Furthermore, LicoB inhibited the increase in type I interferon levels in mice induced by the STING agonist CMA. LicoB significantly reduced systemic inflammation in Trex1−/− mice. Our results show that LicoB, a STING signaling pathway inhibitor, is a promising candidate for the treatment of diseases related to STING signaling pathway activation.

Interferon-stimulated neutrophils as a predictor of immunotherapy response

Despite the remarkable success of anti-cancer immunotherapy, its effectiveness remains confined to a subset of patients-emphasizing the importance of predictive biomarkers in clinical decision-making and further mechanistic understanding of treatment response. Current biomarkers, however, lack the power required to accurately stratify patients. Here, we identify interferon-stimulated, Ly6Ehi neutrophils as a blood-borne biomarker of anti-PD1 response in mice at baseline. Ly6Ehi neutrophils are induced by tumor-intrinsic activation of the STING (stimulator of interferon genes) signaling pathway and possess the ability to directly sensitize otherwise non-responsive tumors to anti-PD1 therapy, in part through IL12b-dependent activation of cytotoxic Tcells. By translating our pre-clinical findings to a cohort of patients with non-small cell lung cancer and melanoma (n= 109), and to public data (n= 1440), we demonstrate the ability of Ly6Ehi neutrophils to predict immunotherapy response in humans with high accuracy (average AUC≈ 0.9). Overall, our study identifies a functionally active biomarker for use in both mice and humans.

Tumor Microenvironment-Responsive Nanoparticles Amplifying STING Signaling Pathway for Cancer Immunotherapy.

Insufficient activation of the stimulator of interferon genes (STING) signaling pathway and profoundly immunosuppressive microenvironment largely limits the effect of cancer immunotherapy. Herein, tumor microenvironment (TME)-responsive nanoparticles (PMM NPs) are exploited that simultaneously harness STING and Toll-like receptor 4 (TLR4) to augment STING activation via TLR4-mediated nuclear factor-kappa B signaling pathway stimulation, leading to the increased secretion of type I interferons (i.e., 4.0-fold enhancement of IFN-β) and pro-inflammatory cytokines to promote a specific T cell immune response. Moreover, PMM NPs relieve the immunosuppression of the TME by decreasing the percentage of regulatory T cells, and polarizing M2 macrophages to the M1 type, thus creating an immune-supportive TME to unleash a cascade adaptive immune response. Combined with an anti-PD-1 antibody, synergistic efficacy is achieved in both inflamed colorectal cancer and noninflamed metastatic breast tumor models. Moreover, rechallenging tumor-free animals with homotypic cells induced complete tumor rejection, indicating the generation of systemic antitumor memory. These TME-responsive nanoparticles may open a new avenue to achieve the spatiotemporal orchestration of STING activation, providing a promising clinical candidate for next-generation cancer immunotherapy.

Protective effects of palbociclib on colitis-associated colorectal cancer.

Chronic or recurrent inflammatory injury to the intestinal mucosa is closely related to inflammation-related colorectal cancer (CRC). This study aimed to examine the protective effects of palbociclib, a stimulator of interferon genes (STING) antagonist, on colitis-related colorectal carcinogenesis. Bioinformatic analyses, including Gene Ontology (GO) enrichment, gene set enrichment analysis (GSEA), and network analysis, were conducted. Male C57BL/6 mice were administered azoxymethane (AOM) and dextran sulfate sodium (DSS), followed by treatment with palbociclib for 6 weeks. The general conditions of mice were observed and recorded. The colon histopathology was assessed based on hematoxylin and eosin (H&E) staining results. Relative messenger RNA (mRNA) expression levels of interferon b1 (Ifnb1), interleukin 6 (Il6), and interleukin 1b (Il1b) in colon were estimated based on quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) analysis. The STING signaling pathway was significantly upregulated in stages III and IV of CRC in The Cancer Genome Atlas (TCGA)-CRC cohort. After treatment with AOM/DSS, the weight of mice decreased significantly, whereas administration of palbociclib partially reversed this trend. The mouse colon treated with AOM/DSS showed significant pathological damages, disorderly epithelial cell structure, atypical hyperplasia, and infiltration of several inflammatory cell types; however, the colon damage was remarkably reduced upon treatment with palbociclib. It was also found that palbociclib almost abolished the increase in the downstream effectors of STING-mediated transcription in the colon tissue treated with AOM/DSS, as evidenced by the transcription levels of Ifnb1, Il6, and Il1b. These findings indicate that the STING pathway is closely associated with CRC. Palbociclib significantly alleviates tumor development in AOM/DSS-induced colitis-associated CRC.

Chlorogenic acid protects against intestinal inflammation and injury by inactivating the mtDNA–cGAS–STING signaling pathway in broilers under necrotic enteritis challenge

This study aimed to determine the effects of chlorogenic acid (CGA) on the growth performance, intestinal health, immune response, and mitochondrial DNA (mtDNA)-cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling pathway in broilers under necrotic enteritis (NE) challenge. The 180 one-day-old male Cobb 500 broilers with similar body weight of 44.59 ± 1.39 g were randomly allocated into 3 groups. The groups were control diet (Control group), control diet + NE challenge (NE group), and control diet + 500 mg/kg CGA + NE challenge (NE + CGA group), with 6 replicates per treatment. All broilers except the Control group were given sporulated coccidian oocysts (d 14) and Clostridium perfringens (d 19-21) by oral gavage. Our findings showed that CGA improved the growth performance and intestinal morphology in broilers under NE challenge. CGA supplementation elevated the barrier function in broilers under NE challenge, which reflected in the decreased serum concentrations of D-lactate and diamine oxidase, and upregulated jejunal protein expression of occludin. CGA supplementation also improved the immune function, which reflected in the increased concentrations and gene expressions of anti-inflammatory factors, and decreased concentrations and gene expressions of proinflammatory factors. CGA supplementation further enhanced intestinal cell proliferation and differentiation, which manifested in the increased number of goblet cells and positive cells of proliferating cell nuclear antigen on d 28 and 42. Furthermore, CGA supplementation decreased the mtDNA (d 42) and mitochondrial reactive oxygen species levels (d 28 and 42), and increased the mitochondrial membrane potential (d 42) and mitochondrial complex I (d 28 and 42) or III (d 28) activity. Broilers challenged with NE had upregulated jejunal protein expressions of cGAS, phospho-TANK-binding kinase 1, and phospho-interferon regulatory factor 7 compared with the Control group, which were downregulated after CGA supplementation. In conclusion, dietary supplementation CGA could protect against intestinal inflammation and injury by reducing the leakage of mtDNA and inactivating the cGAS-STING signaling pathway in broilers under NE challenge.

STING-driven activation of T cells: relevance for the adoptive cell therapy of cancer

Adoptive cell therapy (ACT) can successfully treat hema-topoietic cancers but lacks efficacy against solid tumors. This is due to insufficient T cell infiltration, high tumor heterogeneity, frequent antigen loss with subsequent tumor escape, and the immunosup-pressive tumor microenvironment (TME). Alternative methods to boost the anticancer efficacy of adoptively transferred cells are ac-tively pursued. Among adjuvants that are utilized to stimulate anti-cancer immune responses, ligands of the stimulator of interferon genes (STING) pathway have received increasing attention. STING activation can trigger dendritic cell (DC) activation and endogenous immune responses, thereby preventing tumor escape. Activation of the STING pathway in the context of ACT was accordingly associated with improved T cell trafficking and persistence in the TME com-bined with the reduced presence of immunosuppressive cells. Re-cent findings also suggest cell-intrinsic effects of STING ligands on T cells. Activation of the STING signaling pathway was in this regard shown to enhance effector functions of CD4+ and CD8+ T cells, sug-gesting that the STING signaling could be exploited to harness T cell anticancer functions. In this review, we will discuss how the STING signaling can be used to enhance the anticancer efficacy of ACT.

Chemical Biology Perspectives on STING Agonists as Tumor Immunotherapy.

Stimulator of interferon genes (STING) is a crucial adaptor protein in the innate immune response. STING activation triggers cytokine secretion, including type I interferon and initiates T cell-mediated adaptive immunity. The activated immune system converts "cold tumors" into "hot tumors" that are highly responsive to T cells by recruiting them to the tumor microenvironment, ultimately leading to potent and long-lasting antitumor effects. Unlike most immune checkpoint inhibitors, STING agonists represent a groundbreaking class of innate immune agonists that hold great potential for effectively targeting various cancer populations and are poised to become a blockbuster in tumor immunotherapy. This review will focus on the correlation between the STING signaling pathway and tumor immunity, as well as explore the impact of STING activation on other biological processes. Ultimately, we will summarize the development and optimization of STING agonists from a medicinal chemistry perspective, evaluate their potential in cancer therapy, and identify possible challenges for future advancement.

Discovery of novel amidobenzimidazole derivatives as orally available small molecule modulators of stimulator of interferon genes for cancer immunotherapy

Stimulator of interferon genes (STING) agonists show promise as immunomodulatory agents for cancer therapy. In this study, we report the discovery of a novel orally available STING agonist, SAP-04, that exhibits potent immunomodulatory effects for cancer therapy. By optimizing the amidobenzimidazole core with various pyridine-based heterocyclic substituents, we identified a monomeric variant that displayed more efficient STING agonistic activity than the corresponding dimer. SAP-04 efficiently induced cytokine secretion related to innate immunity by directly binding of the compound to the STING protein, followed by sequential signal transduction for the STING signaling pathway and type I interferon (IFN) responses. Further pharmacological validation in vitro and in vivo demonstrated the potential utility of SAP-04 as an immunomodulatory agent for cancer therapy in vivo. The in vivo anticancer effect was observed in a 4T1 breast tumor syngeneic mouse model through oral administration of the compound. Our findings suggest a possible strategy for developing synthetically accessible monomeric variants as orally available STING agonists.

CGAS-STING signaling pathway promotes hypoxia-induced renal fibrosis by regulating PFKFB3-mediated glycolysis

Hypoxia has long been considered to play an active role in the progression of fibrosis in chronic kidney disease, but its specific mechanism is not fully understood. The stimulator of interferon genes (STING) has been a research hotspot in the fields of tumor, immunity, and infection in recent years, and its role in immune and inflammatory responses related to kidney disease has gradually attracted attention. This study mainly explores the role and mechanism of STING in hypoxia-related renal fibrosis. To address this issue, we stimulated human proximal tubular epithelial (HK-2) cells with hypoxia for 48 h to construct cell models. Meanwhile, C57BL/6J male mice were used to establish a renal fibrosis model induced by renal ischemia-reperfusion injury (IRI). In our present study, we found that the GMP-AMP synthase (cGAS)-STING signaling pathway can promote the progression of renal fibrosis after hypoxic exposure, and this effect is closely related to 6-phosphofructo-2-kinase/fructose-2, 6-bisphosphatase 3 (PFKFB3)-mediated glycolysis. Furthermore, inhibition of both STING and its downstream interferon regulatory factor 3 (IRF3) reversed elevated PFKFB3 expression, thereby attenuating hypoxia-induced renal fibrosis. Taken together, our data suggest that the cGAS-STING-IRF3-PFKFB3 signaling pathway activated under hypoxia may provide new ideas and targets for the treatment of early renal fibrosis.

Inhibitors of Stimulator of Interferon Genes from 2019 to July 2022: An Overview of the Structure and Bioactivity.

Stimulator of interferon genes (STING) plays a vital role in the human innate immune system. Aberrant expression of STING has been proven to be associated with several diseases, such as STING-associated vasculopathy with onset in infancy, Aicardi-Goutieres syndrome, and systemic lupus erythematosus. Therefore, inhibition of the STING signaling pathway can also be expected to provide effective therapeutic strategies for treating specific inflammatory and autoimmune diseases. However, the development of STING inhibitors is still in its infancy. There is still a need for additional efforts toward the discovery of new skeletons and more potent lead compounds for STING inhibition to meet clinical demand. In this review, we provide a summary of STING inhibitors, classified by different structural skeletons, reported in patents published from 2019 to July 2022. In addition, we also focus on the STING inhibitors, representative structures, biological activity, and mechanisms of action.

Borrelia burgdorferic-di-AMP induces type I IFN response in macrophage through the activation of STING signaling pathway

Abstract Lyme disease (LD) which is caused by the spirochete Borrelia burgdorferi (Bb) poses a global health threat. Bb infection induces type I IFN response that is associated with arthritis and other symptoms. However, the ligands, PAMPs, and signaling pathways associated with type I IFN production by Bb are poorly characterized. Stimulator of Interferon Genes (STING) signaling pathway is an intracellular surveillance pathway that detects c-di-nucleotides (CDNs) produced by pathogens through STING and induces type I IFN production. Bb produces CDNs and hence it has the potential to activate the STING signaling pathway. In this study, the role of c-di-AMP in the elicitation of type I IFN response to Bb infection was elucidated. The RAW cell line was infected with Bb and activation of STING signaling was measured by detecting the activation of downstream proteins (pSTING, pTBK1, pIRF3 & pNF-κB), proinflammatory cytokines (IL6, TNF-α) and Type I IFN (IFN-β) response using ELISA, western blotting, immunostaining, and Luciferase Reporter assay. Bb infection to macrophage results in c-di-AMP mediated elicitation of type I IFN response. The induction level of type I IFN response was dependent on the level of c-di-AMP as the Bb mutant strain producing higher c-di-AMP level induced higher cytokine production. Interestingly, c-di-AMP released into the BSK-II medium during the culture of Bb could also stimulate the production of type I IFN response. The induction of type I IFN by c-di-AMP was dependent on STING protein as the RAW STING KO cell line showed a reduction in the level of IFN-β. In conclusion, our results show that Bb-produced c-di-AMP is a major PAMP that triggers type I interferon production in macrophage by activation of the STING signaling pathway.

P2rx1 deficiency alleviates acetaminophen-induced acute liver failure by regulating the STING signaling pathway

AimsPurinergic signaling-mediated mitochondria dysfunction and innate immune-mediated inflammation act as triggers during acetaminophen (APAP)-induced liver injury (AILI). However, the underlying mechanisms by which purinoceptor regulates mitochondria function and inflammation response in the progression of AILI remains unclear.MethodsFirst, the hepatic level of purinergic receptor P2X 1 (P2RX1) was identified in the DILI patients and APAP-induced WT mice. P2rx1 knockout (KO) mice (P2rx1−/−) with 300 mg/kg APAP challenge were used for the analysis of the potential role of P2RX1 in the progression of AILI. Administration of DMX, the activator of stimulator of interferon genes (STING), was performed to investigate the effects of the STING-related pathway on APAP-treated P2rx1−/− mice.ResultsThe elevated hepatic P2RX1 levels were found in DILI patients and the AILI mice. P2rx1 depletion offered protection against the initial stages of AILI, mainly by inhibiting cell death and promoting inflammation resolution, which was associated with alleviating mitochondria dysfunction. Mechanistically, P2rx1 depletion could inhibit STING-TANK-binding kinase 1 (TBK1)-P65 signaling pathways in vivo. We then showed that DMX-mediated STING activation could greatly aggravate the liver injury of P2rx1−/− mice treated with APAP.ConclusionOur data confirmed that P2RX1 was inducted during AILI, identified P2RX1 as a novel regulator in mitochondria dysfunction and STING pathways, and suggested a promising therapeutic approach for AILI involving the blockade of P2RX1.Graphical abstract1. It first demonstrated the protective effects of P2rx1 deficiency on acetaminophen-induced liver injury (AILI).2. P2rx1 knockout alleviates mitochondria function and promotes inflammation resolution after APAP treatment.3. It first reported the regulation of P2RX1 on the STING signaling pathway in the progress of AILI.4. P2RX1 blockade is a promising therapeutic strategy for AILI.

Abstract 3600: MET-mediated STING activation regulates EMT and NF-ΚB pathway in non-small cell lung cancer

Abstract The cyclic GAMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway is known to have anti-tumor activity by activating the innate immune response against cytosolic double-stranded DNA (dsDNA). The regulating mechanism of STING remains unclear, and a pro-tumorigenic effect of STING pathway was recently reported. In this study, we investigated the expression of STING by MET and a novel role of the STING pathway in non-small cell lung cancer (NSCLC). The Cancer Genome Atlas (TCGA) and Cancer Cell Line Encyclopedia (CCLE) analysis showed that cGAS/STING pathway is enriched and STING expression is higher in MET-overexpressing tumors. Western blot for NSCLC cells and immunohistochemistry for NSCLC tumor tissues showed positive correlation between MET and STING expression in NSCLC cells. MET-overexpression and a MET agonist (HGF) treatment increased STING expression and CXCL10 and IFNβ expression and secretion, whereas MET-knockdown and a MET inhibitor (capmatinib) treatment decreased STING expression in NSCLC cells. In MET-positive and STING-positive cells, a STING agonist (poly-dAdT and diABZI) treatment led to increased activation of STING signaling pathway. In EBC-1 cells, MET knockdown decreased STING expression and STING-agonist-induced STING-pathway activation and cytokine production. To further investigate the role STING in NSCLC, EBC-1 cells were transfected with STING siRNA and submitted to RNS-seq. Gene set enrichment analysis revealed that several pathways were affected by STING expression. Epithelial-mesenchymal transition (EMT) and TNFα-signaling via NF-κB signaling were significantly downregulated in STING-knockdowned cells. In vitro experiments using EBC-1 cells, STING overexpression increased SLUG and TWIST1 expression and migration of cells, whereas STING knockdown decreased SLUG and TWIST1 expression and migration of cells. In summary, this study demonstrated that MET and STING expression were positively correlated with each other in NSCLC and MET overexpression increased STING expression and subsequent activation upon STING agonist stimulation. In addition, STING contributed to EMT in NSCLC. Citation Format: Seungchan Mun, Bogyeong Han, HyunKyung Ahn, Jaemoon Koh, Sehui Kim, DooHyun Chung, YoonKyung Jeon. MET-mediated STING activation regulates EMT and NF-ΚB pathway in non-small cell lung cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3600.

A role of STING signaling in obesity-induced lung inflammation

BackgroundIt is established that pulmonary disorders are comorbid with metabolic disorders such as obesity. Previous studies show that the stimulator of interferon genes (STING) signaling plays crucial roles in obesity-induced chronic inflammation via TANK-binding kinase 1 (TBK1) pathways. However, it remains unknown whether and how the STING signaling is implicated in the inflammatory processes in the lung in obesity.MethodsHuman lung tissues were obtained from obese patients (n = 3) and controls (n = 3). Mice were fed with the high-fat diet or regular control diet to establish the diet-induced obese (DIO) and lean mice, and were treated with C-176 (a specific STING inhibitor) or vehicle respectively. The lung macrophages were exposed to palmitic acid (PA) in vitro. The levels of STING singaling and metabolic inflammation factors were detected and anlyzed.ResultsWe find that STING+/CD68+ macrophages are increased in lung tissues in patients with obesity. Our data also show that the expressions of STING and the levels of proinflammatory cytokines are increased both in lung tissues and bronchoalveolar lavage fluid (BALF) in obesity compared to controls, and inhibition of the STING blunted the obesity-induced lung inflammation. Mechanistically, our data demonstrate that the STING signaling pathway is involved in the PA-induced inflammation through the STING-TBK1-IRF3 (interferon regulatory factor 3)/NF-κB (nuclear factor kappa B) pathways in the lung macrophages.ConclusionsOur results collectively suggest that the STING signaling contributes to obesity-associated inflammation by stimulating proinflammatory processes in lung macrophages, one that may serve as a therapeutic target in ameliorating obesity-related lung dysfunctions.

Proteomics analysis uncovers plasminogen activator PLAU as a target of the STING pathway for suppression of cancer cell migration and invasion

The stimulator of interferon genes (STING) pathway is vital for immune defense against pathogen invasion and cancer. Although ample evidence substantiates that the STING signaling pathway plays an essential role in various cancers via cytokines, no comprehensive investigation of secretory proteins regulated by the STING pathway has been conducted hitherto. Herein, we identify 24 secretory proteins significantly regulated by the STING signaling pathway through quantitative proteomics. Mechanistic analyses reveal that STING activation inhibits the translation of urokinase-type plasminogen activator (PLAU) via the STING-PERK-eIF2α signaling axis. PLAU is highly expressed in a variety of cancers and promotes the migration and invasion of cancer cells. Notably, the activation of STING inhibits cancer cell migration and invasion by suppressing PLAU. Collectively, these results provide novel insights into the anticancer mechanism of the STING pathway, offering a theoretical basis for precision therapy for this patient population.

Low STING expression promotes endometrial stromal cell invasion and migration via the STING/IRF-3/IFN-β1 pathway in eutopic endometrium of women with endometriosis

Aims: The primary aim of the current study was to elucidate the function of the stimulator of interferon genes (STING) in the eutopic endometrium of women with endometriosis. Materials and Methods: STING expression and signaling pathways were verified by western blot analysis and immunohistochemistry after si-STING treatment. Cell proliferation and invasion and migration were assessed using 5-ethynyl-2’-deoxyuridine and transwell assays, respectively. Results: Within endometriosis tissues, STING was primarily expressed in the stroma of the eutopic endometrium and glandular epithelium of the ectopic endometrium. However, STING expression was significantly lower in the eutopic endometrium of patients with endometriosis compared to controls (p < 0.05). Additionally, cell proliferation (0.2866 ± 0.01470 vs. 0.6911 ± 0.01796, ****p < 0.0001), invasion (130.0 ± 6.296 vs. 424.1 ± 22.31, **** p < 0.0001), and migration (82.93 ± 6.940 vs. 82.93 ± 6.940, **** p < 0.0001) were significantly increased in the si-STING groups. Moreover, following si-STING transfection, the expression of phosphorylated IRF-3 and TBK1 that are involved in STING/IRF3/IFNb1 signaling pathway decreased. The addition of exogenous IFN-β1 effectively increased stromal cell invasion (IFN-β1-NC vs. IFN-β1-si-STING 274.7 ± 7.767 vs. 135.7 ± 12.63, ***p < 0.0001) and migration (IFN-β1-NC and IFN-β1-si-STING 28.53 ± 3.625 vs. 28.53 ± 3.625, ***p < 0.0001) without significantly impacting cell proliferation (si-STING vs. IFN-1β-si-STING 0.6874 ± 0.02081 vs. 0.7187 ± 0.02638, p = 0.795). Conclusions: The STING signaling pathway plays an important role in endometrial stromal cell proliferation, invasion and migration associated with endometriosis.

Abstract 15420: Cgas-Sting Pathway-Mediated Cholesterol Metabolism Promotes Atherosclerosis Formation

Introduction: The mechanisms underlying macrophage lipid accumulation and foam cell formation, the critical step in atherosclerosis initiation, remain to be understood. The cGAS (cyclic GMP-AMP synthase)-STING (stimulator of interferon genes) signaling pathway triggers potent inflammation in response to cytosolic DNA accumulation. Hypothesis: In this study, we found that the cGAS-STING signaling pathway can promote macrophage lipid accumulation and atherosclerosis development. Methods: We developed an atherosclerosis mice model by a single intraperitoneal injection of an adeno-associated virus (AAV) containing a mouse PCSK9 gain-of-function mutation D377Y. Results: In the descending aorta of patients and aortic root of atherosclerotic mice, we detected profound cytosolic DNA accumulation that was associated with the activation of cGAS -STING in both human and mouse atherosclerotic plaques. In cultured macrophages, DNA uptake by macrophages activated the cGAS-STING pathway, which induced the biosynthesis of fatty acids and cholesterol. Interestingly, we found that STING can bind to SREBP2 (sterol regulatory element-binding protein 2) through SCAP (SREBP2 cleavage activating protein) and promote its cleavage and nuclear translocation, and subsequent induction of genes in fatty acid and cholesterol biosynthesis. Finally, in an AAV-PCSK9/high-fat diet-induced atherosclerosis model, cGas -/- and SMC- Sting -/- mice exhibited a reduction of SREBP2 activation and lipid content in macrophages and a reduction in atherosclerosis burden. Conclusions: Our findings indicated that DNA and cGAMP from damaged cells serve as a danger molecule that, by activating the cGAS-STING cytosolic DNA sensing signaling, promotes macrophage lipid biosynthesis and accumulation, contributing to atherosclerosis development.