Shuangdan Jiedu Decoction improved LPS-induced acute lung injury by regulating both cGAS-STING pathway and inflammasome.

ETHNOPHARMACOLOGICAL RELEVANCE: Shuangdan Jiedu Decoction (SJD) is a formula composed of six Chinese herbs with heat-removing and detoxifying, antibacterial, and anti-inflammatory effects, which is clinically used in the therapy of various inflammatory diseases of the lungs including COVID-19, but the therapeutic material basis of its action as well as its molecular mechanism are still unclear. AIM OF THE STUDY: The study attempted to determine the therapeutic effect of SJD on LPS-induced acute lung injury (ALI), as well as to investigate its mechanism of action and assess its therapeutic potential for the cure of inflammation-related diseases in the clinical setting. MATERIALS AND METHODS: We established an ALI model by tracheal drip LPS, and after the administration of SJD, we collected the bronchoalveolar lavage fluid (BALF) and lung tissues of mice and examined the expression of inflammatory factors in them. In addition, we evaluated the effects of SJD on the cyclic guanosine monophosphate-adenosine monophosphate synthase -stimulator of interferon genes (cGAS-STING) and inflammasome by immunoblotting and real-time quantitative polymerase chain reaction (RT-qPCR). RESULTS: We demonstrated that SJD was effective in alleviating LPS-induced ALI by suppressing the levels of pro-inflammatory cytokines in the BALF, improving the level of lung histopathology and the number of neutrophils, as well as decreasing the inflammatory factor-associated gene expression. Importantly, we found that SJD could inhibit multiple stimulus-driven activation of cGAS-STING and inflammasome. Further studies showed that the Chinese herbal medicines in SJD had no influence on the cGAS-STING pathway and inflammasome alone at the formulated dose. By increasing the concentration of these herbs, we observed inhibitory effects on the cGAS-STING pathway and inflammasome, and the effect exerted was maximal when the six herbs were combined, indicating that the synergistic effects among these herbs plays a crucial role in the anti-inflammatory effects of SJD. CONCLUSIONS: Our research demonstrated that SJD has a favorable protective effect against ALI, and its mechanism of effect may be associated with the synergistic effect exerted between six Chinese medicines to inhibit the cGAS-STING and inflammasome abnormal activation. These results are favorable for the wide application of SJD in the clinic as well as for the development of drugs for ALI from herbal formulas.

A manganese-doped layered double hydroxide loaded with lactate oxidase and DNA repair inhibitors for synergistically enhanced tumor immunotherapy.

Tumor immunotherapy has gained more and more attention in tumor treatment. However, the accumulation of lactic acid in tumor tissue inhibits the response of immune cells to form an immunosuppressive microenvironment (ISME). To reverse the ISME, an acid-responsive nanoplatform (termed as MLLN@HA) is reported for synergistically enhanced tumor immunotherapy. MLLN@HA is constructed by the co-loading of lactate oxidase (LOX) and DNA repair inhibitor (NU7441) in a manganese-doped layered double hydroxide (Mn-LDH), and then modified with hyaluronic acid (HA) for tumor-targeted delivery. After endocytosis by tumor cells, MLLN@HA decomposes and releases LOX, NU7441 and Mn2+ ions in the acidic tumor microenvironment. The released LOX catalyzes the conversion of lactic acid into hydrogen peroxide (H2O2), which not only alleviates the ISME, but also provides reactants for the Mn2+-mediated Fenton-like reaction to enhance chemodynamic therapy (CDT). Released NU7441 prevents CDT-induced DNA damage from being repaired, thereby increasing double-stranded DNA (dsDNA) fragments within tumor cells. Importantly, the released Mn2+ ions enhance the sensitivity of cyclic GMP-AMP synthase (cGAS) to dsDNA fragments, and activate the stimulator of interferon genes (STING) to induce an anti-tumor immune response. Such an orchestrated immune-boosting strategy ultimately achieves effective tumor growth inhibition and prevents tumor lung metastasis. STATEMENT OF SIGNIFICANCE: To improve the efficacy of tumor immunotherapy, an innovative acid-responsive MLLN@HA nanoplatform was developed for synergistically enhanced tumor immunotherapy. The MLLN@HA actively targets to tumor cells through the interaction of HA with CD44, and then degrades to release LOX, NU7441 and Mn2+ ions in the acidic tumor microenvironment. The released LOX generates H2O2 for the Mn2+-mediated Fenton reaction and reverses the ISME by consuming lactate. NU7441 prevents DNA damage repair, leading to an increased concentration of free DNA fragments, while Mn2+ ions activate the cGAS-STING pathway, enhancing the systemic anti-tumor immune response. The orchestrated immune-boosting nanoplatform effectively inhibits tumor growth and lung metastasis, presenting a promising strategy for cancer treatment.

Tumor microenvironment-responsive manganese-based nano-modulator activate the cGAS-STING pathway to enhance innate immune system response.

BACKGROUND: Manganese ions (Mn2+) combined with adjuvants capable of damaging and lysing tumor cells form an antitumor nano-modulator that enhances the immune efficacy of cancer therapy through the cascade activation of the cyclic GMP-AMP interferon gene synthase-stimulator (cGAS-STING) pathway, which underscores the importance of developing antitumor nano-modulators, which induce DNA damage and augment cGAS-STING activity, as a critical future research direction. METHODS AND RESULTS: We have successfully synthesized an antitumor nano-modulator, which exhibits good dispersibility and biosafety. This nano-modulator is engineered by loading manganese dioxide nanosheets (M-NS) with zebularine (Zeb), known for its immunogenicity-enhancing effects, and conducting targeted surface modification using hyaluronic acid (HA). After systemic circulation to the tumor site, Mn2+, Zeb, and reactive oxygen species (ROS) are catalytically released in the tumor microenvironment by H+ and H2O2. These components can directly or indirectly damage the DNA or mitochondria of tumor cells, thereby inducing programmed cell death. Furthermore, they promote the accumulation of double-stranded DNA (dsDNA) in the cytoplasm, enhancing the activation of the cGAS-STING signalling pathway and boosting the production of type I interferon and the secretion of pro-inflammatory cytokines. Additionally, Zeb@MH-NS enhances the maturation of dendritic cells, the infiltration of cytotoxic T lymphocytes, and the recruitment of natural killer cells at the tumor site. CONCLUSIONS: This HA-modified manganese-based hybrid nano-regulator can enhance antitumor therapy by boosting innate immune activity and may provide new directions for immunotherapy and clinical translation in cancer.

Arsenic trioxide induces innate immune response and inflammatory response in chicken liver via cGAS-STING/NF-κB pathway.

Arsenic is a toxic metal-like element widely used in the pesticide, preservative and semiconductor industries. However, accumulation of arsenic through the food chain can cause serious damage to animal and human health. However, the toxic mechanism of arsenic-induced hepatotoxicity in chickens is not clear, and the present study aimed to investigate the potential role of cGAS-STING and NF-κB pathways on inflammatory injury in chicken liver. In this study, 75 white-feathered broilers were divided into a control group, a low-dose arsenic group (4 mg/kg) and a high-dose arsenic group (8 mg/kg) to investigate the toxic effects of arsenic on chicken liver. In this study, we found that pathological changes such as inflammatory cell infiltration and vesicular degeneration occurred in the liver when exposed to ATO. Crucially, exposure to ATO triggered the cGAS-STING pathway and markedly raised the levels of mRNA and protein expression of cGAS, STING, TBK1, and IRF7. The type I interferon response was also triggered. Simultaneously, STING induced the activation of the conventional NF-κB signaling pathway and stimulated the expression of genes associated with inflammation, such as IL-6, TNF-α and IL-1ß. In summary, the induction of inflammatory responses via cGAS-STING and NF-κB signaling pathways under high ATO exposure provides new ideas for further studies on the toxicological mechanisms of arsenic.

Metal complex lipid-based nanoparticles deliver metabolism-regulating lomitapide to overcome CTC immune evasion via activating STING pathway.

Activating the cGAS-STING pathway of circulating tumor cell clusters (CTC clusters) represents a promising strategy to mitigate metastases. To fully exploit the potential of cholesterol-regulating agents in activating CTCs' STING levels, we developed a nanoparticle (NP) composed of metal complex lipid (MCL). This design includes MCL-miriplatin to increase NP stiffness and loads lomitapide (lomi) modulating cholesterol levels, resulting in the creation of PLTs@Pt-lipid@lomi NPs. MCL-miriplatin not only enhances lomi's eliciting efficacy on STING pathway but also increases NPs' stiffness, thus a vital factor affecting the penetration into CTC clusters to further boost lomi's ability. Demonstrated by cy5 tracking experiments, PLTs@Pt-lipid@lomi NPs quickly attach to cancer cell via platelet membrane anchorage, penetrate deep into the spheres, and reach the subcellular endoplasmic reticulum where lomi regulates cholesterol. Additionally, these NPs have been shown to track CTCs in the bloodstream, a capability not demonstrated by the free drug. PLTs@Pt-lipid@lomi NPs more efficiently activate the STING pathway and reduce CTC stemness compared to free lomi. Ultimately, PLTs@Pt-lipid@lomi NPs reduce metastasis in a post-surgery animal model. While cholesterol-regulating agents are limited in efficacy when being repositioned as immunomodulatory agents, this MCL-composing NP strategy demonstrates the potential to effectively deliver these agents to target CTC clusters.

Schisandrin C enhances type I IFN response activation to reduce tumor growth and sensitize chemotherapy through antitumor immunity.

With the advancing comprehension of immunology, an increasing number of immunotherapies are being explored and implemented in the field of cancer treatment. The cGAS-STING pathway, a crucial element of the innate immune response, has been identified as pivotal in cancer immunotherapy. We evaluated the antitumor effects of Schisandra chinensis lignan component Schisandrin C (SC) in 4T1 and MC38 tumor-bearing mice, and studied the enhancing effects of SC on the cGAS-STING pathway and antitumor immunity through RNA sequencing, qRT-PCR, and flow cytometry. Our findings revealed that SC significantly inhibited tumor growth in models of both breast and colon cancer. This suppression of tumor growth was attributed to the activation of type I IFN response and the augmented presence of T cells and NK cells within the tumor. Additionally, SC markedly promoted the cGAS-STING pathway activation induced by cisplatin. In comparison to cisplatin monotherapy, the combined treatment of SC and cisplatin exhibited a greater inhibitory effect on tumor growth. The amplified chemotherapeutic efficacy was associated with an enhanced type I IFN response and strengthened antitumor immunity. SC was shown to reduce tumor growth and increase chemotherapy sensitivity by enhancing the type I IFN response activation and boosting antitumor immunity, which enriched the research into the antitumor immunity of S. chinensis and laid a theoretical basis for its application in combating breast and colon cancer.

Fecal microbiome transplantation alleviates manganese-induced neurotoxicity by altering the composition and function of the gut microbiota via the cGAS-STING/NLRP3 pathway.

Manganese (Mn) is an environmental pollutant, and overexposure can cause neurodegenerative disorders similar to Alzheimer's disease and Parkinson's disease that are characterized by ß-amyloid (Aß) overexpression, Tau hyperphosphorylation and neuroinflammation. However, the mechanisms of Mn neurotoxicity are not clearly defined. In our study, a knockout mouse model of Mn exposure combined with gut flora-induced neurotoxicity was constructed to investigate the effect of gut flora on Mn neurotoxicity. The results showed that the levels of Tau, p-Tau and Aß in the hippocampus of C57BL/6 mice were greater than those in the hippocampus of control mice after 5 weeks of continuous exposure to manganese chloride (Mn content of 200 mg/L). Transplanted normal and healthy fecal microbiota from mice significantly downregulated Tau, p-Tau and Aß expression and ameliorated brain pathology. Moreover, Mn exposure activated the cGAS-STING pathway and altered the cecal microbiota profile, characterized by an increase in Clostridiales, Pseudoflavonifractor, Ligilactobacillus and Desulfovibrio, and a decrease in Anaerotruncus, Eubacterium_ruminantium_group, Fusimonas and Firmicutes, While fecal microbiome transplantation (FMT) treatment inhibited this pathway and restored the microbiota profile. FMT alleviated Mn exposure-induced neurotoxicity by inhibiting activation of the NLRP3 inflammasome triggered by overactivation of the cGAS-STING pathway. Deletion of the cGAS and STING genes and FMT altered the gut microbiota composition and its predictive function. Phenotypic prediction revealed that FMT markedly decreased the abundances of anaerobic and stress-tolerant bacteria and significantly increased the abundances of facultative anaerobic bacteria and biofilm-forming bacteria after blocking the cGAS-STING pathway compared to the Mn-exposed group. FMT from normal and healthy mice ameliorated the neurotoxicity of Mn exposure, possibly through alterations in the composition and function of the microbiome associated with the cGAS-STING/NLRP3 pathway. This study provides a prospective direction for future research on the mechanism of Mn neurotoxicity.

The cGAS-STING pathway in COPD: targeting its role and therapeutic potential.

Chronic obstructive pulmonary disease(COPD) is a gradually worsening and fatal heterogeneous lung disease characterized by airflow limitation and increasingly decline in lung function. Currently, it is one of the leading causes of death worldwide. The consistent feature of COPD is airway inflammation. Several inflammatory factors are known to be involved in COPD pathogenesis; however, anti-inflammatory therapy is not the first-line treatment for COPD. Although bronchodilators, corticosteroids and roflumilast could improve airflow and control symptoms, they could not reverse the disease. The cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) signaling pathway plays an important novel role in the immune system and has been confirmed to be a key mediator of inflammation during infection, cellular stress, and tissue damage. Recent studies have emphasized that abnormal activation of cGAS-STING contributes to COPD, providing a direction for new treatments that we urgently need to develop. Here, we focused on the cGAS-STING pathway, providing insight into its molecular mechanism and summarizing the current knowledge on the role of the cGAS-STING pathway in COPD. Moreover, we explored antagonists of cGAS and STING to identify potential therapeutic strategies for COPD that target the cGAS-STING pathway.

Mitochondria-targeting nanozyme for catalytical therapy and radiotherapy with activation of cGAS-STING.

BACKGROUND: Overcoming radio-resistance and enhance radio-sensitivity to obtain desired therapeutic outcome plays an important role in treating cancer. METHODS: Here we constructed a versatile enzyme-like nano-radiosensitizer MDP. MDP is composed of MnCO decorated and Ru-based nanozyme with triphenylphosphine (TPP) group coordinated on the surface. RESULTS: Due to the mitochondria-targeting ability of TPP and enhanced permeability and retention effect (EPR) effect of MDP, MDP accumulated in the mitochondria of tumor cells. Therefore, quantities of reactive oxygen species were produced via multiple enzyme-like properties including peroxidase (POD) and catalase (CAT) in a tumor microenvironment mimicking status. In additional, more energy of radiation ionizing was deposed in tumor site via Compton effect and secondary electron scattering by Ru element. Impressively, it was disclosed that the nanozyme can act as a cGAS-STING agonist to provoke immune response of the system, which hereby further elevated this combined therapy. CONCLUSIONS: Collectively, we fabricated a novel nanozyme with POD and CAT mimicking properties for the combination therapy of catalytical therapy, radiotherapy as well as immune therapy to eliminate cancer.

DNA sensors in metabolic and cardiovascular diseases: Molecular mechanisms and therapeutic prospects.

DNA sensors generally initiate innate immune responses through the production of type I interferons. While extensively studied for host defense against invading pathogens, emerging evidence highlights the involvement of DNA sensors in metabolic and cardiovascular diseases. Elevated levels of modified, damaged, or ectopically localized self-DNA and non-self-DNA have been observed in patients and animal models with obesity, diabetes, fatty liver disease, and cardiovascular disease. The accumulation of cytosolic DNA aberrantly activates DNA signaling pathways, driving the pathological progression of these disorders. This review highlights the roles of specific DNA sensors, such as cyclic AMP-GMP synthase and stimulator of interferon genes (cGAS-STING), absent in melanoma 2 (AIM2), toll-like receptor 9 (TLR9), interferon gamma-inducible protein 16 (IFI16), DNA-dependent protein kinase (DNA-PK), and DEAD-box helicase 41 (DDX41) in various metabolic disorders. We explore how DNA signaling pathways in both immune and non-immune cells contribute to the development of these diseases. Furthermore, we discuss the intricate interplay between metabolic stress and immune responses, offering insights into potential therapeutic targets for managing metabolic and cardiovascular disorders. Understanding the mechanisms of DNA sensor signaling in these contexts provides a foundation for developing novel interventions aimed at mitigating the impact of these pervasive health issues.

Alteration of cGAS-STING signaling pathway components in the mouse cortex and hippocampus during healthy brain aging.

The cGAS-STING pathway is a pivotal element of the innate immune system, recognizing cytosolic DNA to initiate the production of type I interferons and pro-inflammatory cytokines. This study investigates the alterations of the cGAS-STING signaling components in the cortex and hippocampus of mice aged 24 and 108 weeks. In the cortex of old mice, an increase in the dsDNA sensor protein cGAS and its product 2'3'-cGAMP was observed, without corresponding activation of downstream signaling, suggesting an uncoupling of cGAS activity from STING activation. This phenomenon may be attributed to increased dsDNA concentrations in the EC neurons, potentially arising from nuclear DNA damage. Contrastingly, the hippocampus did not exhibit increased cGAS activity with aging, but there was a notable elevation in STING levels, particularly in microglia, neurons and astrocytes. This increase in STING did not correlate with enhanced IRF3 activation, indicating that brain inflammation induced by the cGAS-STING pathway may manifest extremely late in the aging process. Furthermore, we highlight the role of autophagy and its interplay with the cGAS-STING pathway, with evidence of autophagy dysfunction in aged hippocampal neurons leading to STING accumulation. These findings underscore the complexity of the cGAS-STING pathway's involvement in brain aging, with regional variations in activity and potential implications for neurodegenerative diseases.

Overexpression of ESYT3 improves radioimmune responses through activating cGAS-STING pathway in lung adenocarcinoma.

BACKGROUND: Radiotherapy can modulate systemic antitumor immunity, while immune status in the tumor microenvironment also influences the efficacy of radiotherapy, but relevant molecular mechanisms are poorly understood in lung adenocarcinoma (LUAD). METHODS: In this study, we innovatively proposed a radiotherapy response classification for LUAD, and discovered ESYT3 served as a tumor suppressor and radioimmune response sensitizer. ESYT3 expression was measured both in radioresistant and radiosensitive LUAD tissues and cells. The influence of ESYT3 on radiotherapy sensitivity and resistance was then investigated. Interaction between ESYT3 and STING was evaluated through multiple immunofluorescent staining and coimmunoprecipitation, and downstream molecules were further analyzed. In vivo models were constructed to assess the combination treatment efficacy of ESYT3 overexpression with radiotherapy. RESULTS: We found that radioresistant subtype presented immunosuppressive state and activation of DNA damage repair pathways than radiosensitive subtype. ESYT3 expression was remarkably attenuated both in radioresistant LUAD tissues and cells. Clinically, low ESYT3 expression was linked with radioresistance. Overexpression of ESYT3 enabled to alleviate radioresistance, and sensitize LUAD cells to DNA damage induced by irradiation. Mechanically, ESYT3 directly interacted with STING, and activated cGAS-STING signaling, subsequently increasing the generation of type I IFNs as well as downstream chemokines CCL5 and CXCL10, thus improving radioimmune responses. The combination treatment of ESYT3 overexpression with radiotherapy had a synergistic anticancer effect in vitro and in vivo. CONCLUSIONS: In summary, low ESYT3 expression confers resistance to radiotherapy in LUAD, and its overexpression can improve radioimmune responses through activating cGAS-STING-dependent pathway, thus providing an alternative combination therapeutic strategy for LUAD patients.

Circulating Cell-Free DNA Promotes Inflammation in Patients with Dermatomyositis with Anti-NXP2 Antibodies via the cGAS/STING Pathway.

OBJECTIVES: Dermatomyositis (DM) is a rare type I interferon (IFN-I)-driven autoimmune disease, and anti-nuclear matrix protein 2 (NXP2) antibody is related to severe muscle disease and poor prognosis. Circulating cell-free DNA (ccf-DNA), including ccf-mitochondrial DNA and ccf-nuclear DNA, activates cGAS/STING pathway to induce IFN-I production in autoimmune diseases. We investigated whether serum-derived ccf-DNA played a pathogenic role on skeletal muscle in anti-NXP2 antibody-positive DM. METHODS: Serum ccf-DNA levels were measured, and correlations between ccf-DNA and clinicopathological indicators were performed. RNA sequencing, immunofluorescence, western blotting and RT-qPCR were performed on skeletal muscle samples. The serum-induced expression of p-STING in C2C12 cells was assessed in vitro. RESULTS: We found that increased ccf-DNA levels were positively correlated with MYOACT scores in anti-NXP2 antibody-positive DM. RNA sequencing and immunofluorescence results revealed that the cytosolic DNA-sensing pathway was upregulated and that increased cytosolic dsDNA was colocalised with cGAS in skeletal muscle in anti-NXP2 antibody-positive DM. Western blot analysis revealed activation of the cGAS/STING pathway in patients with perifascicular atrophy (PFA) but not in patients without PFA. RT-qPCR showed increased IFN-I scores in both patients with PFA and patients without PFA. Sera from patients with PFA increased p-STING expression in C2C12 cells, and DNase I treatment and STING inhibitor efficiently inhibited p-STING expression, respectively. CONCLUSIONS: Increased ccf-DNA levels may be potential biomarkers for monitoring disease activity in anti-NXP2 antibody-positive DM. Activation of the cGAS/STING pathway is associated with PFA. Our findings identify the pathogenic role of ccf-DNA on skeletal muscle via the cGAS/STING pathway.

Role of Microglial Mitophagy in Alleviating Postoperative Cognitive Dysfunction: a Mechanistic Study.

Postoperative cognitive dysfunction (POCD), a common complication following anesthesia and surgery, is influenced by hippocampal neuroinflammation and microglial activation. Mitophagy, a process regulating inflammatory responses by limiting the accumulation of damaged mitochondria, plays a significant role. This study aimed to determine whether regulating microglial mitophagy and the cGAS-STING pathway could alleviate cognitive decline after surgery. Exploratory laparotomy was performed to establish a POCD model using mice. Western blotting, immunofluorescence staining, transmission electron microscopy, and mt-Keima assays were used to examine microglial mitophagy and the cGAS-STING pathway. Quantitative polymerase chain reaction (qPCR) was used to detect inflammatory mediators and cytosolic mitochondrial DNA (mtDNA) levels in BV2 cells. Exploratory laparotomy triggered mitophagy and enhanced the cGAS-STING pathway in mice hippocampi. Pharmacological treatment reduced microglial activation, neuroinflammation, and cognitive impairment after surgery. Mitophagy suppressed the cGAS-STING pathway in mice hippocampi. In vitro, microglia-induced inflammation was mediated by mitophagy and the cGAS-STING pathway. Small interfering RNA (siRNA) of PINK1 hindered mitophagy activation and facilitated the cytosolic release of mtDNA, resulting in the initiation of the cGAS-STING pathway and innate immune response. Microglial mitophagy inhibited inflammatory responses via the mtDNA-cGAS-STING pathway inducing microglial mitophagy and inhibiting the mtDNA-cGAS-STING pathway may be an effective therapeutic approach for patients with POCD.

Enzyme-Dynamic Extracellular Vesicles for Metalloimmunotherapy of Malignant Pleural Effusions.

Malignant pleural effusions (MPEs) are hard to treat, and their onset usually signals terminal cancer. Immunotherapies hold promise but must overcome the immunosuppressive MPE microenvironment. Herein, we treat MPEs via synergistically combining two emerging cancer therapy modalities: enzyme-dynamic therapy (EDT) and metalloimmunotherapy. To do so, a nanoplatform termed "A-R-SOME" was developed which comprises MPE-targeted M1 type extracellular vesicles (EVs) loaded with (1) a manganese-based superoxide dismutase (SOD) enzyme, (2) stimulator of interferon genes (STING) agonist diABZI-2, and (3) signal transducer and an activator of transcription 3 (STAT3) small interfering RNA. Endogenous reactive oxygen species within tumors induced immunogenic cell death by EDT, along with STING activation by both Mn and diABZI-2, and suppression of the STAT3 pathway. Systemically administered A-R-SOME alleviated the MPE immunosuppressive microenvironment, triggered antitumor systemic immunity, and long-term immune memory, leading to the complete eradication of MPE and pleural tumors with 100% survival rate in an aggressive murine model. A-R-SOME-induced immune effects were also observed in human patient-derived MPE, pointing toward the translation potential of A-R-SOME as an experimental malignancy treatment.

Optimized Bionic Drug-Delivery-Inducing Immunogenic Cell Death and cGAS-STING Pathway Activation for Enhanced Photodynamic-Chemotherapy-Driven Immunotherapy in Prostate Cancer.

Prostate cancer presents as a challenging disease, as it is often characterized as an immunologically "cold" tumor, leading to suboptimal outcomes with current immunotherapeutic approaches in clinical settings. Photodynamic therapy (PDT) harnesses reactive oxygen species generated by photosensitizers (PSs) to disrupt the intracellular redox equilibrium. This process induces DNA damage in both the mitochondria and nucleus, activating the process of immunogenic cell death (ICD) and the cGAS-STING pathway. Ultimately, this cascade of events leads to the initiation of antitumor immune responses. Nevertheless, existing PSs face challenges, including suboptimal tumor targeting, aggregation-induced quenching, and insufficient oxygen levels in the tumor regions. To this end, a versatile bionic nanoplatform has been designed for the simultaneous delivery of the aggregation-induced emission PS TPAQ-Py-PF6 and paclitaxel (PTX). The cell membrane camouflage of the nanoplatform leads to its remarkable abilities in tumor targeting and cellular internalization. Upon laser irradiation, the utilization of TPAQ-Py-PF6 in conjunction with PTX showcases a notable and enhanced synergistic antitumor impact. Additionally, the nanoplatform has the capability of initiating the cGAS-STING pathway, leading to the generation of cytokines. The presence of damage-associated molecular patterns induced by ICD collaborates with these aforementioned cytokines lead to the recruitment and facilitation of dendritic cell maturation. Consequently, this elicits a systemic immune response against tumors. In summary, this promising strategy highlights the use of a multifunctional biomimetic nanoplatform, combining chemotherapy, PDT, and immunotherapy to enhance the effectiveness of antitumor treatment.

Metal-Phenolic Nanomaterial with Organelle-Level Precision Primes Antitumor Immunity via mtDNA-dependent cGAS-STING Activation.

New generation of nanomaterials with organelle-level precision provide significant promise for targeted attacks on mitochondria, exhibiting remarkable therapeutic potency. Here, we report a novel amphiphilic phenolic polymer (PF) for the mitochondria-targeted photodynamic therapy (PDT), which can trigger excessive mitochondrial DNA (mtDNA) damages by the synergistic action of oxidative stress and furan-mediated DNA cross-linking. Moreover, the phenolic units on PF enable further self-assembly with Mn2+ via metal-phenolic coordination to form metal-phenolic nanomaterial (PFM). We focus on the synergistic activation of the cGAS-STING pathway by Mn2+ and tumor-derived mtDNA in tumor-associated macrophages (TAMs), and subsequently repolarizing M2-like TAMs to M1 phenotype. We highlight that PFM facilitates the cGAS-STING-dependent immunity at the organelle level for potent antitumor efficacy.

STING activation increases the efficiency of temozolomide in PTEN harbouring glioblastoma cells.

Background/aim: Glioblastoma is one of the most aggressive tumours, resistant to all applied therapy regiments and prone to relapse. Median survival rates are therefore only expressed as months. STING agonists are immunomodulatory molecules that activate type I interferon expression, making them potentially useful in regulating the tumour microenvironment. Since PTEN serves as a critical phosphatase in activating interferon-regulating transcription factors and is frequently mutated in glioblastoma cells, this study aimed to investigate STING activation in glioblastoma cell lines, examining whether they harbour the PTEN protein or not.°. Materials and methods: T98G and U118MG glioblastoma cell lines were treated with the 2'3'-c-di-AM(PS)2(Rp,Rp) STING agonist together with or without the chemotherapeutic agent temozolomide. cGAS/STING pathway components were subsequently analysed using qRT-PCR, western blot, and ELISA methods. Results: Our results showed that PTEN-harbouring T98G cells responded well to STING activation, leading to increased temozolomide efficacy. In contrast, STING activation in U118MG cells did not affect the response to temozolomide. mRNA expression levels of STING, IRF3, NF-KB, and RELA genes were significantly increased at the combined treatment groups in T98G cell line. Conversely, combined treatment with STING agonist and temozolomide did not affect mRNA expression levels of cGAS/STING pathway genes in U118MG cells. Conclusion: Our data offers new evidence suggesting that STING agonists can effectively be used to increase temozolomide response in the presence of PTEN protein. Therefore, increased GBM therapy success rates can be achieved by employing the PTEN expression status as a predictive biomarker before treating patients with a chemotherapeutic agent in combination with STING agonist.

Acidity-activatable dynamic hybrid nanoplatforms derived from extracellular vesicles of M1 macrophages enhance cancer immunotherapy through synergistic triple immunotherapy.

Immunotherapy exhibits considerable promise for sustained tumor reduction. However, current cancer immunotherapy methods elicit limited responses due to the inadequate immunogenicity exhibited by cancer cells. This obstacle may be addressed using nanoplatforms that can activate synergistic therapies (photodynamic therapy and ferroptosis) in response to the acidic pH of the tumor microenvironment. We previously developed an amphiphilic photosensitizer, SR780, which displays satisfactory photodynamic effects. This photosensitizer is inactivated when bound to Fe3+ (SR780Fe) but is activated upon release in mildly acidic conditions. In this study, M1 macrophage-derived extracellular vesicles (EVs) were fused with REV and SR780Fe-loaded liposomes (REV@SR780Fe@Lip) to form REV@SR780Fe@LEV hybrid nanovesicles. Further modification with the RS17 peptide for tumor targeting enabled a combination of photodynamic therapy, ferroptosis, and cGAS-STING pathway activation, resulting in enhanced antitumor efficacy through a synergistic effect. Upon laser irradiation, REV@SR780Fe@LEV-RS17 demonstrated antitumor effects in 4T1 breast cancer models, including the inhibition of lung and liver metastasis, as well as prevention of tumor recurrence.

Light-Activated In Situ Vaccine with Enhanced Cytotoxic T Lymphocyte Infiltration and Function for Potent Cancer Immunotherapy.

In situ cancer vaccination is an attractive strategy that stimulates protective antitumor immunity. Cytotoxic T lymphocytes (CTLs) are major mediators of the adaptive immune defenses, with critical roles in antitumor immune response and establishing immune memory, and are consequently extremely important for in situ vaccines to generate systemic and lasting antitumor efficacy. However, the dense extracellular matrix and hypoxia in solid tumors severely impede the infiltration and function of CTLs, ultimately compromising the efficacy of in situ cancer vaccines. To address this issue, a robust in situ cancer vaccine, Au@MnO2 nanoparticles (AMOPs), based on a gold nanoparticle core coated with a manganese dioxide shell is developed. The AMOPs modulated the unfavorable tumor microenvironment (TME) to restore CTLs infiltration and function and efficiently induced immunogenic cell death. The Mn2+-mediated stimulator of the interferon genes pathway can be activated to further augment the therapeutic efficacy of the AMOPs. Thus, the AMOPs vaccine successfully elicited long-lasting antitumor immunity to considerably inhibit primary, recurrent, and metastatic tumors. This study not only highlights the importance of revitalizing CTLs efficacy against solid tumors but also makes progress toward overcoming TME barriers for sustained antitumor immunity.