Activation of the cGAS-STING pathway combined with CRISPR-Cas9 gene editing triggering long-term immunotherapy

Self-oxygenating nanoplatform integrating CRISPR/Cas9 gene editing and immune activation for highly efficient photodynamic therapy

Photodynamic therapy (PDT) has arisen as a promising method due to its spatiotemporal precision and minimal invasiveness. It encounters significant obstacles in solid tumors due to hypoxia-induced therapeutic resistance and the self-protective mechanisms of cancer cells facilitated by MutT homolog 1 (MTH1), an enzyme involved in oxidative damage repair. Herein, we fabricate a tumor-microenvironment responsive CRISPR nanoplatform based on hollow mesoporous manganese dioxide (H-MnO2) for PDT. This platform utilizes H-MnO2 to produce oxygen (O2) through the decomposition of hydrogen peroxide (H2O2) in TME, thereby mitigating hypoxia and enhancing reactive oxygen species (ROS) generation. The high concentration of glutathione (GSH) and hyaluronidase (HAase) in TME induces the release of CRISPR/Cas9 ribonucleoproteins (RNP) to target the MTH1 gene, thereby impairs oxidative damage repair pathways and amplifys ROS-mediated cytotoxicity. The released Mn2+ ions function as immunomodulatory agents, activate innate immune responses via stimulating STING signal pathway. In vitro, IHMRH NPs markedly increased intracellular O2 levels, ROS production, lipid peroxidation and DNA damage, leading to tumor cell death, immune activation, and effective gene editing. In vivo, the nanoplatform suppressed tumor growth, diminished MTH1 gene expression, stimulated dendritic cell (DC) maturation through immunogenic cell death (ICD). This multimodal nanosystem may amplifies oxidative stress, collaborates with innate and adaptive immune activation to surpass the constraints of traditional PDT. The research presents a novel framework for cancer combination therapy by systematically integrating nanotechnology with precision gene editing.

Advances in nanoplatform-based multimodal combination therapy activating STING pathway for enhanced anti-tumor immunotherapy

Activation of the cyclic GMP-AMP synthase(cGAS)-stimulator of interferon genes (STING) has great potential to promote antitumor immunity. As a major effector of the cell to sense and respond to the aberrant presence of cytoplasmic double-stranded DNA (dsDNA), inducing the expression and secretion of type I interferons (IFN) and STING, cGAS-STING signaling pathway establishes an effective natural immune response, which is one of the fundamental mechanisms of host defense in organisms. In addition to the release of heterologous DNA due to pathogen invasion and replication, mitochondrial damage and massive cell death can also cause abnormal leakage of the body's own dsDNA, which is then recognized by the DNA receptor cGAS and activates the cGAS-STING signaling pathway. However, small molecule STING agonists suffer from rapid excretion, low bioavailability, non-specificity and adverse effects, which limits their therapeutic efficacy and in vivo application. Various types of nano-delivery systems, on the other hand, make use of the different unique structures and surface modifications of nanoparticles to circumvent the defects of small molecule STING agonists such as fast metabolism and low bioavailability. Also, the nanoparticles are precisely directed to the focal site, with their own appropriate particle size combined with the characteristics of passive or active targeting. Herein, combined with the cGAS-STING pathway to activate the immune system and kill tumor tissues directly or indirectly, which help maximize the use of the functions of chemotherapy, photothermal therapy(PTT), chemodynamic therapy(CDT), and radiotherapy(RT). In this review, we will discuss the mechanism of action of the cGAS-STING pathway and introduce nanoparticle-mediated tumor combination therapy based on the STING pathway. Collectively, the effective multimodal nanoplatform, which can activate cGAS-STING pathway for enhanced anti-tumor immunotherapy, has promising avenue clinical applications for cancer treatment.

Manganese-Based Nanotherapeutics for Targeted Treatment of Breast Cancer

Breast cancer (BC) is one of the most common cancers among women and is associated with high mortality. Traditional modalities, including surgery, radiotherapy, and chemotherapy, have achieved certain advancements but continue to combat challenges including harm to healthy tissues, resistance to treatment, and adverse drug reactions. The rapid advancements in nanotechnology recently facilitated the exploration of innovative strategies for breast cancer therapy. Manganese-based nanotherapeutics have attracted great attention because of their unique characteristics such as tunable structures/morphologies, versatility, magnetic/optical properties, strong catalytic activities, excellent biodegradability, and biocompatibility. In this review, we highlighted different types of Mn-based nanotherapeutics to modulate TME, including metal-immunotherapy, alleviating tumor hypoxia, and increasing reactive oxygen species production, and we emphasized its role in magnetic resonance imaging (MRI)-guided therapy, photoacoustic imaging, and theranostic-based therapy along with a therapeutic carrier, all of which were discussed in the context of breast cancer. Hopefully, the present review will provide insights into the current landscape and future directions of multifunctional applications of Mn-based nanotherapeutics in the field of breast cancer treatment.

Advances in polymer nanomaterials targeting cGAS-STING pathway for enhanced cancer immunotherapy

Cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)-stimulator of interferon genes (STING) pathway has been recognized as a promising target for cancer immunotherapy. Although various STING agonists have been developed, their clinical applications are still severely impeded by various issues, such as non-specific accumulation, adverse effects, rapid clearance, etc. In recent years, the emergence of nanomaterials has profoundly revolutionized STING agonists delivery, which promote tumor-targeted delivery, boost the immunotherapeutic effects and reduce systemic toxicity of STING agonists. In particular, polymer nanomaterials possess inherent advantages including controllable structure, tunable function and degradability. These properties afford them the capacity to serve as delivery vehicles for small-molecule STING agonists. Furthermore, the superior characteristics of polymer nanomaterials can enable their utilization as a novel STING agonist to stimulate anti-tumor immunity. In this review, the molecular mechanisms of cGAS-STING pathway activation are discussed. The recent development of small-molecules STING agonists is described. Then polymer nanomaterials are discussed as carriers for STING agonists in cancer immunotherapy, including polymersomes, polymer micelles, polymer capsules, and polymer nanogels. Additionally, polymer nanomaterials are identified as a novel class of STING agonists for efficient cancer immunotherapy, encompassing both polymer materials and polymer-STING agonists conjugates. The review also presents the combination of polymer-based cGAS-STING immunotherapy with chemotherapy, radiotherapy, phototherapy (both photodynamic and photothermal), chemodynamic therapy, and other therapeutic strategies. Furthermore, the discussion highlights recent advancements targeting the cGAS-STING pathway in clinically approved polymer nanomaterials and corresponding potent innovations. Finally, the potential challenges and perspectives of polymer nanomaterials for activating cGAS-STING pathway are outlined, emphasizing the critical scientific issue and hoping to offer guidance for their clinical translation.

Biologically logic-gated Trojan-horse strategy for personalized triple-negative breast cancer precise therapy by selective ferroptosis and STING pathway provoking

Amidst the therapeutic quandaries associated with triple-negative breast cancer (TNBC), an aggressive malignancy distinguished by its immune resistance and limited treatment avenues, the urgent need for innovative solutions is underscored. To conquer the dilemma, we present a groundbreaking approach that ingeniously employs DNA-fragments-containing exosomes (DNA-Exo) and the concept of "biological logic-gates" to achieve precise homing and controlled selective activation of ferroptosis and stimulator interferon genes (STING) pathways. Leveraging insights from our previous research, a nano-Trojan-horse, Fe0@HMON@DNA-Exo, is engineered via in situ Fe0 synthesis within the glutathione (GSH)-responsiveness degradable hollow mesoporous organosilica nanoparticles (HMON) and subsequently enveloped in DNA-Exo derived from 7-ethyl-10-hydroxycamptothecin (SN38)-treated 4T1 cells. Emphasizing the precision of our approach, the DNA-Exo ensures specific 'homing' to TNBC cells, rendering a targeted delivery mechanism. Concurrently, the concept of "biological logic-gates" is employed to dictate a meticulous and selective activation of STING in antigen-presenting cells (APCs) under OR logic-gating with robust immune response and Fe0-based ferroptosis in TNBC cells under AND logic-gating with reactive oxygen species (ROS) storm generation. In essence, our strategy exhibits great potential in transforming the "immunologically cold" nature of TNBC, enabling precise control over cellular responses, illuminating a promising therapeutic paradigm that is comprehensive and productive in pursuing precision oncology and paving the way for personalized TNBC therapies.

Metal-Phenolic Network Hydrogel Vaccine Platform for Enhanced Humoral Immunity against Lethal Rabies Virus

Rabies, caused by rabies virus (RABV), is a zoonotic disease with a high mortality rate that has attracted global attention with the goal of eradication by 2030. However, rabies can only be prevented by appropriate and multiple vaccinations, which impede widespread vaccination in developing countries due to its high expenditure. Designing single-dose vaccines is a pressing challenge in the prevention of rabies and other infectious diseases. Herein, a metal-phenolic network (MPN)-based hydrogel vaccine (designated as CGMR) was developed to stimulate potent humoral immunity against RABV infection by a single immunization, resulting in 4.3-fold and 1.8-fold enhancements of virus-neutralizing antibody compared with that induced by inactivated RABV and alum adjuvant. The CGMR, cross-linked by phenol-modified chitosan with manganese ion, could prolong residence time by confining the antigen to the network of hydrogel, acting as a "hydrogel antigen depot". It also stimulated the activation of the cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)-stimulator of interferon gene (STING) pathway, facilitating dendritic cell maturation and antigen presentation. The vaccine formulation recruited immunocytes and activated the germinal center, enhancing and sustaining humoral immune responses against the virulent RABV challenge. Collectively, this injectable manganese-based hydrogel vaccine provides a universal and ideal avenue for rabies and other infectious diseases.

Application of nanoparticles with activating STING pathway function in tumor synergistic therapy

Although immunotherapy is currently one of the most promising methods for cancer treatment, its clinical application is limited due to issues such as excessive autoimmune responses and lack of specificity. Therefore, there is a need to improve immunotherapy by integrating emerging medical technologies with traditional treatments. The activation of the cGAS-STING pathway plays a crucial role in innate immunity and antiviral defense, making it highly promising for immunotherapy and attracting significant attention. In recent years, research on nanomaterials and immunotherapy has achieved groundbreaking progress in the medical field. Due to their unique size, shape, stiffness, surface effects, and quantum size effects, nanomaterials can either carry STING activators or directly activate the STING pathway, offering new opportunities for tumor-specific immunotherapy. These unique advantages of nanomaterials have opened up broader prospects for nanoparticle-based therapies targeting the STING pathway. This paper summarizes the current research on utilizing nanomaterials to activate the STING pathway, detailing the characteristics, classifications, and different approaches for targeting tumor cells. Additionally, it focuses on the latest advancements in combined nanotherapies based on cGAS-STING pathway activation, including the integration of nanomaterial-mediated STING pathway activation with immunotherapy, radiotherapy, chemotherapy, targeted therapy, and photodynamic therapy. This provides new ideas for nanoparticle-based combination therapies involving the STING pathway.

Enhanced antitumor efficacy of STING agonist MSA-2 by lipid nanoparticles delivering circular IL-23 mRNA and platinum-modified MSA-2 combination

A next-generation STING agonist MSA-2 is a promising tumor immunotherapy strategy. However, the methods for improving the anti-tumor efficacy of MSA-2 are a lot of effort. We have demonstrated antitumor effect of platinum-modified MSA-2 (MSA-2-Pt) was better than MSA-2. Here, we combined lipid nanoparticles delivering circular IL-23 mRNA (LNP@cIL-23) and MSA-2-Pt strategy, which showed good antitumor efficacy. Firstly, we synthesized a new series of ionizable phospholipids and formulated and optimized an LNP36 for delivering circular IL-23 mRNA. Then, the combination of LNP36@cIL-23 mRNA and MSA-2-Pt induced tumor cell death and immune activation in the tumor with a single i.t. injection. Finally, the combination of LNP36@cIL-23 mRNA and MSA-2-Pt significantly decreased the melanoma B16F10 tumor and prolonged the survival, demonstrating significant anti-tumor effects. This finding provides promising new avenues for STING activation strategies in tumor immunotherapy.

Metal-based smart nanosystems in cancer immunotherapy

Metals are an emerging topic in cancer immunotherapy that have shown great potential in modulating cancer immunity cycle and promoting antitumor immunity by activating the intrinsic immunostimulatory mechanisms which have been identified in recent years. The main challenge of metal-assisted immunotherapy lies in the fact that the free metals as ion forms are easily cleared during circulation, and even cause systemic metal toxicity due to the off-target effects. With the rapid development of nanomedicine, metal-based smart nanosystems (MSNs) with unique controllable structure become one of the most promising delivery carriers to solve the issue, owing to their various endogenous/external stimuli-responsiveness to release free metal ions for metalloimmunotherapy. In this review, the state-of-the-art research progress in metal-related immunotherapy is comprehensively summarized. First, the mainstream mechanisms of MSNs-assisted immunotherapy will be delineated. The immunological effects of certain metals and categorization of MSNs with different characters and compositions are then provided, followed by the representative exemplar applications of MSNs in cancer treatment, and synergistic combination immunotherapy. Finally, we conclude this review with a summary of the remaining challenges associated with MSNs and provide the authors' perspective on their further advances.

Radiation-activated PD-L1 aptamer-functionalized nanoradiosensitizer to potentiate antitumor immunity in combined radioimmunotherapy and photothermal therapy

Reactive oxygen species (ROS)-mediated immunogenic cell death (ICD) is crucial in radioimmunotherapy by boosting innate antitumor immunity. However, the hypoxic tumor microenvironment (TME) often impedes ROS production, limiting the efficacy of radiotherapy. To tackle this challenge, a combination therapy involving radiotherapy and immune checkpoint blockade (ICB) with anti-programmed death-ligand 1 (PD-L1) has been explored to enhance antitumor effects and reprogram the immunosuppressive TME. Here, we introduce a novel PD-L1 aptamer-functionalized nanoradiosensitizer designed to augment radiotherapy by increasing X-ray deposition specifically at the tumor site. This innovative X-ray-activated nanoradiosensitizer, comprising gold-MnO2 nanoflowers, efficiently enhances ROS generation under single low-dose radiation and repolarizes M2-like macrophages, thereby boosting antitumor immunity. Additionally, the ICB inhibitor BMS-202 synergizes with the PD-L1 aptamer-assisted nanoradiosensitizer to block the PD-L1 receptor, promoting T cell activation. Furthermore, this nanoradiosensitizer exhibits exceptional photothermal conversion efficiency, amplifying the ICD effect. The PD-L1-targeted nanoradiosensitizer effectively inhibits primary tumor growth and eliminates distant tumors, underscoring the potential of this strategy in optimizing both radioimmunotherapy and photothermal therapy.

Targeted Delivery of STING Agonist via Albumin Nanoreactor Boosts Immunotherapeutic Efficacy against Aggressive Cancers

Background: Activating the cytosolic innate immune sensor, the cGAS-STING pathway, holds great promise for enhancing antitumor immunity, particularly in combination with immune checkpoint inhibitors (ICIs). However, the clinical application of STING agonists is often hindered by poor tumor accumulation, limited cellular uptake, and rapid clearance. To address these challenges, we developed a human serum albumin (HSA)-based nanoreactor system for the efficient delivery of the STING agonist SR-717, aiming to improve its antitumor efficacy. Methods: Using a biomineralization technique, we encapsulated SR-717 within HSA nanocages to form SH-NPs. These nanoparticles were characterized in terms of size, stability, and cellular uptake, and their ability to activate the STING pathway was assessed in both in vitro and in vivo models, including freshly isolated human renal tumor tissues. In vivo antitumor efficacy was evaluated in a murine renal tumor model, and immune responses were measured. Results: SH-NPs exhibited enhanced stability, efficient cellular uptake, and superior tumor accumulation compared to free SR-717. They robustly activated the STING pathway, as evidenced by increased phosphorylation of TBK1 and IRF3, along with elevated IFN-β production. Additionally, SH-NPs reshaped the immunosuppressive tumor microenvironment, promoting T-cell-mediated immunity and improving the therapeutic efficacy of checkpoint blockade in murine models. The validation in human renal tumor tissues further highlighted their potential for clinical translation. Importantly, SH-NPs were well tolerated with minimal systemic toxicity. Conclusions: This study underscores the potential of HSA-based nanoparticles for the targeted delivery of STING agonists, effectively enhancing antitumor immunity and improving cancer immunotherapy outcomes. SH-NPs offer a promising solution to the limitations of current STING agonists in clinical settings.

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.

Carrageenan-ferrocene-eicosapentaenoic acid composite hydrogel induce ferroptosis and apoptosis for anti-tumor recurrence and metastasis

The immune-suppressive microenvironment of solid tumors is a key factor limiting the effectiveness of immunotherapy, which seriously threatens human life and health. Ferroptosis and apoptosis are key cell-death pathways implicated in cancers, which can synergistically activate tumor immune responses. Here, we developed a multifunctional composite hydrogel (CE-Fc-Gel) based on the self-assembly of poloxamer 407, cystamine-linked ιota-carrageenan (CA)-eicosapentaenoic acid (EPA), and ferrocene (Fc). CE-Fc-Gel improved targeting in tumor microenvironment due to its disulfide bonds. Moreover, CE-Fc-Gel promoted lipid peroxidation, enhanced reactive oxygen species (ROS) production, and decreased glutathione peroxidase 4 (GPX4), inducing ferroptosis by the synergistic effect of Fc and EPA. CE-Fc-Gel induced apoptosis and immunogenic cell death (ICD), thereby promoting dendritic cells (DCs) maturation and T cell infiltration. As a result, CE-Fc-Gel significantly inhibited primary and metastatic tumors in vivo. Our findings provide a novel strategy for enhancing tumor immunotherapy by combining apoptosis, ferroptosis, and ICD.

Mitophagy and cGAS-STING crosstalk in neuroinflammation

Mitophagy, essential for mitochondrial health, selectively degrades damaged mitochondria. It is intricately linked to the cGAS-STING pathway, which is crucial for innate immunity. This pathway responds to mitochondrial DNA and is associated with cellular stress response. Our review explores the molecular details and regulatory mechanisms of mitophagy and the cGAS-STING pathway. We critically evaluate the literature demonstrating how dysfunctional mitophagy leads to neuroinflammatory conditions, primarily through the accumulation of damaged mitochondria, which activates the cGAS-STING pathway. This activation prompts the production of pro-inflammatory cytokines, exacerbating neuroinflammation. This review emphasizes the interaction between mitophagy and the cGAS-STING pathways. Effective mitophagy may suppress the cGAS-STING pathway, offering protection against neuroinflammation. Conversely, impaired mitophagy may activate the cGAS-STING pathway, leading to chronic neuroinflammation. Additionally, we explored how this interaction influences neurodegenerative disorders, suggesting a common mechanism underlying these diseases. In conclusion, there is a need for additional targeted research to unravel the complexities of mitophagy-cGAS-STING interactions and their role in neurodegeneration. This review highlights potential therapies targeting these pathways, potentially leading to new treatments for neuroinflammatory and neurodegenerative conditions. This synthesis enhances our understanding of the cellular and molecular foundations of neuroinflammation and opens new therapeutic avenues for neurodegenerative disease research.

Overcoming T Cell Exhaustion in Tumor Microenvironment via Immune Checkpoint Modulation with Nano-Delivery Systems for Enhanced Immunotherapy

Immune checkpoint blockade (ICB) therapy for tumors has arisen in growing interest. However, the low response rate of tumors to ICB is mainly attributed to the inhibitory infiltration of immune cells in the tumor microenvironment (TME). Despite the promising benefits of ICB, the therapeutic effects of antibodies are dependent on a high dose and long-term usage in the clinic, thereby leading to immune-related adverse effects. Accordingly, ICB combined with nano-delivery systems could be used to overcome T cell exhaustion, which reduces the side effects and the usage of antibodies with higher response rates in patients. In this review, the authors aim to overcome T cell exhaustion in TME via immune checkpoint modulation with nano-delivery systems for enhanced immunotherapy. Several strategies are summarized to combine ICB and nano-delivery systems to further enhance immunotherapy: a) expressing immune checkpoint on the surface of nano-delivery systems; b) loading immune checkpoint inhibitors into nano-delivery systems; c) loading gene-editing technology into nano-delivery systems; and d) nano-delivery systems mediated immune checkpoint modulation. Taken together, ICB combined with nano-delivery systems might be a promising strategy to overcome T cell exhaustion in TME for enhanced immunotherapy.

Targeting cytokine and chemokine signaling pathways for cancer therapy

Cytokines are critical in regulating immune responses and cellular behavior, playing dual roles in both normal physiology and the pathology of diseases such as cancer. These molecules, including interleukins, interferons, tumor necrosis factors, chemokines, and growth factors like TGF-β, VEGF, and EGF, can promote or inhibit tumor growth, influence the tumor microenvironment, and impact the efficacy of cancer treatments. Recent advances in targeting these pathways have shown promising therapeutic potential, offering new strategies to modulate the immune system, inhibit tumor progression, and overcome resistance to conventional therapies. In this review, we summarized the current understanding and therapeutic implications of targeting cytokine and chemokine signaling pathways in cancer. By exploring the roles of these molecules in tumor biology and the immune response, we highlighted the development of novel therapeutic agents aimed at modulating these pathways to combat cancer. The review elaborated on the dual nature of cytokines as both promoters and suppressors of tumorigenesis, depending on the context, and discussed the challenges and opportunities this presents for therapeutic intervention. We also examined the latest advancements in targeted therapies, including monoclonal antibodies, bispecific antibodies, receptor inhibitors, fusion proteins, engineered cytokine variants, and their impact on tumor growth, metastasis, and the tumor microenvironment. Additionally, we evaluated the potential of combining these targeted therapies with other treatment modalities to overcome resistance and improve patient outcomes. Besides, we also focused on the ongoing research and clinical trials that are pivotal in advancing our understanding and application of cytokine- and chemokine-targeted therapies for cancer patients.

Stimulus-Responsive Nanodelivery and Release Systems for Cancer Gene Therapy: Efficacy Improvement Strategies

Introduction of exogenous genes into target cells to overcome various tumor diseases caused by genetic defects or abnormalities and gene therapy, a new treatment method, provides a promising strategy for tumor treatment. Over the past decade, gene therapy has made exciting progress; however, it still faces the challenge of low nucleic acid delivery and release efficiencies. The emergence of nonviral vectors, primarily nanodelivery and release systems (NDRS), has resulted in a historic breakthrough in the application of gene therapy. NDRS, especially stimulus-responsive NDRS that can respond in a timely manner to changes in the internal and external microenvironment (eg, low pH, high concentration of glutathione/reactive oxygen species, overexpressed enzymes, temperature, light, ultrasound, and magnetic field), has shown excellent loading and release advantages in the precision and efficiency of tumor gene therapy and has been widely applied. The only disadvantage is that poor transfection efficiency limits the in-depth application of gene therapy in clinical practice, owing to the presence of biological barriers in the body. Therefore, this review first introduces the development history of gene therapy, the current obstacles faced by gene delivery, strategies to overcome these obstacles, and conventional vectors, and then focuses on the latest research progress in various stimulus-responsive NDRS for improving gene delivery efficiency. Finally, the future challenges and prospects that stimulus-responsive NDRS may face in clinical application and transformation are discussed to provide references for enhancing in-depth research on tumor gene therapy.

Stage-specificity of STING activation in intrahepatic cholangiocarcinoma determines the efficacy of its agonism

Intrahepatic cholangiocarcinoma (iCCA) is an aggressive cancer with an extremely poor prognosis, and new treatment options are needed. Recently, immunotherapy has emerged as an efficient treatment against malignant tumors, but less effective in iCCA. Activation of stimulator of interferon genes (STING) signaling could reignite immunologically inert tumors, but the expression and role of STING in iCCA remains to be determined. Here, we show STING is expressed in iCCA, and patients with high expression of STING in early-stage iCCA have a longer overall survival than those have low expression. Increased immune cell infiltration in early-stage iCCA corresponds to elevated STING expression. In mice iCCA models, treatment with the STING agonist MSA-2 show stage-specific inhibitory effects on tumors, with beneficial effects in early-stage tumors but not with advanced-stage cancer. This discrepancy was associated with greater programmed cell death ligand 1 (PD-L1) expression in advanced-stage tumors. Combination therapy targeting PD-L1 and MSA-2 strikingly reduced tumor burden in such tumors compared to either monotherapy. Cumulatively, these data demonstrate that STING agonism monotherapy improves the immune landscape of the tumor microenvironment in early-stage iCCA, while combination therapy ameliorates advanced-stage iCCA.

A next-generation STING agonist MSA-2: From mechanism to application

The stimulator of interferon genes (STING) connects the innate and adaptive immune system and plays a significant role in antitumor immunity. Over the past decades, endogenous and CDN-derived STING agonists have been a hot topic in the research of cancer immunotherapies. However, these STING agonists are either in infancy with limited biological effects or have failed in clinical trials. In 2020, a non-nucleotide STING agonist MSA-2 was identified, which exhibited satisfactory antitumor effects in animal studies and is amenable to oral administration. Due to its distinctive binding mode and enhanced bioavailability, there have been accumulating interests and an array of studies on MSA-2 and its derivatives, spanning its structure-activity relationship, delivery systems, applications in combination therapies, etc. Here, we provide a comprehensive review of MSA-2 and interventional strategies based on this family of STING agonists to help more researchers extend the investigation on MSA-2 in the future.

Tumor microenvironment responsive nano-herb and CRISPR delivery system for synergistic chemotherapy and immunotherapy

Chemoresistance remains a significant challenge for effective breast cancer treatment which leads to cancer recurrence. CRISPR-directed gene editing becomes a powerful tool to reduce chemoresistance by reprogramming the tumor microenvironment. Previous research has revealed that Chinese herbal extracts have significant potential to overcome tumor chemoresistance. However, the therapeutic efficacy is often limited due to their poor tumor targeting and in vivo durability. Here we have developed a tumor microenvironment responsive nanoplatform (H-MnO2(ISL + DOX)-PTPN2@HA, M(I + D)PH) for nano-herb and CRISPR codelivery to reduce chemoresistance. Synergistic tumor inhibitory effects were achieved by the treatment of isoliquiritigenin (ISL) with doxorubicin (DOX), which were enhanced by CRISPR-based gene editing to target protein tyrosine phosphatase non-receptor type 2 (PTPN2) to initiate long-term immunotherapy. Efficient PTPN2 depletion was observed after treatment with M(I + D)PH nanoparticles, which resulted in the recruitment of intratumoral infiltrating lymphocytes and an increase of proinflammatory cytokines in the tumor tissue. Overall, our nanoparticle platform provides a diverse technique for accomplishing synergistic chemotherapy and immunotherapy, which offers an effective treatment alternative for malignant neoplasms.

Development and verification of a manganese metabolism- and immune-related genes signature for prediction of prognosis and immune landscape in gastric cancer

Background

Gastric cancer (GC) poses a global health challenge due to its widespread prevalence and unfavorable prognosis. Although immunotherapy has shown promise in clinical settings, its efficacy remains limited to a minority of GC patients. Manganese, recognized for its role in the body's anti-tumor immune response, has the potential to enhance the effectiveness of tumor treatment when combined with immune checkpoint inhibitors.

Methods

Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases was utilized to obtain transcriptome information and clinical data for GC. Unsupervised clustering was employed to stratify samples into distinct subtypes. Manganese metabolism- and immune-related genes (MIRGs) were identified in GC by univariate Cox regression and least absolute shrinkage and selection operator (LASSO) regression analysis. We conducted gene set variation analysis, and assessed the immune landscape, drug sensitivity, immunotherapy efficacy, and somatic mutations. The underlying role of NPR3 in GC was further analyzed in the single-cell RNA sequencing data and cellular experiments.

Results

GC patients were classified into four subtypes characterized by significantly different prognoses and tumor microenvironments. Thirteen genes were identified and established as MIRGs, demonstrating exceptional predictive effectiveness in GC patients. Distinct enrichment patterns of molecular functions and pathways were observed among various risk subgroups. Immune infiltration analysis revealed a significantly greater abundance of macrophages and monocytes in the high-risk group. Drug sensitivity analysis identified effective drugs for patients, while patients in the low-risk group could potentially benefit from immunotherapy. NPR3 expression was significantly downregulated in GC tissues. Single-cell RNA sequencing analysis indicated that the expression of NPR3 was distributed in endothelial cells. Cellular experiments demonstrated that NPR3 facilitated the proliferation of GC cells.

Conclusion

This is the first study to utilize manganese metabolism- and immune-related genes to identify the prognostic MIRGs for GC. The MIRGs not only reliably predicted the clinical outcome of GC patients but also hold the potential to guide future immunotherapy interventions for these patients.

Manganese-based nanomaterials promote synergistic photo-immunotherapy: green synthesis, underlying mechanisms, and multiple applications

Single phototherapy and immunotherapy have individually made great achievements in tumor treatment. However, monotherapy has difficulty in balancing accuracy and efficiency. Combining phototherapy with immunotherapy can realize the growth inhibition of distal metastatic tumors and enable the remote monitoring of tumor treatment. The development of nanomaterials with photo-responsiveness and anti-tumor immunity activation ability is crucial for achieving photo-immunotherapy. As immune adjuvants, photosensitizers and photothermal agents, manganese-based nanoparticles (Mn-based NPs) have become a research hotspot owing to their multiple ways of anti-tumor immunity regulation, photothermal conversion and multimodal imaging. However, systematic studies on the synergistic photo-immunotherapy applications of Mn-based NPs are still limited; especially, the green synthesis and mechanism of Mn-based NPs applied in immunotherapy are rarely comprehensively discussed. In this review, the synthesis strategies and function of Mn-based NPs in immunotherapy are first introduced. Next, the different mechanisms and leading applications of Mn-based NPs in immunotherapy are reviewed. In addition, the advantages of Mn-based NPs in synergistic photo-immunotherapy are highlighted. Finally, the challenges and research focus of Mn-based NPs in combination therapy are discussed, which might provide guidance for future personalized cancer therapy.

Self-Metallized Whole Cell Vaccines Prepared by Microfluidics for Bioorthogonally Catalyzed Antitumor Immunotherapy

Tumor whole cell, carrying a complete set of tumor-associated antigens and tumor-specific antigens, has shown great potential in the construction of tumor vaccines but is hindered by the complex engineering means and limited efficacy to cause immunity. Herein, we provided a strategy for the self-mineralization of autologous tumor cells with palladium ions in microfluidic droplets, which endowed the engineered cells with both immune and catalytic functions, to establish a bioorthogonally catalytic tumor whole-cell vaccine. This vaccine showed strong inhibition both in the occurrence and recurrence of tumor by invoking the immediate antitumor immunity and building a long-term immunity.

Nanomaterial-mediated modulation of the cGAS-STING signaling pathway for enhanced cancer immunotherapy

Despite the current promise of immunotherapy, many cancer patients still suffer from challenges such as poor immune response rates, resulting in unsatisfactory clinical efficacy of existing therapies. There is an urgent need to combine emerging biomedical discoveries and innovations in traditional therapies. Modulation of the cGAS-STING signalling pathway represents an important innate immunotherapy pathway that serves as a crucial DNA sensing mechanism in innate immunity and viral defense. It has attracted increasing attention as an emerging target for cancer therapy. The recent advancements in nanotechnology have led to the significant utilization of nanomaterials in cancer immunotherapy, owing to their exceptional physicochemical properties such as large specific surface area and efficient permeability. Given the rapid development of cancer immunotherapy driven by the cGAS-STING activation, this study reviews the latest research progress in employing nanomaterials to modulate this signaling pathway. Based on the introduction of the main activation mechanisms of cGAS-STING pathway, this review focuses on nanomaterials that mediate the agonists involved and effectively activate this signaling pathway. In addition, combination nanotherapeutics based on the activation of the cGAS-STING signaling pathway are also discussed, including emerging strategies combining nanoformulated agonists with chemotherapy, radiotherapy as well as other immunomodulation in tumor targeting therapy. STATEMENT OF SIGNIFICANCE: Given the rapid development of cancer immunotherapy driven by the cGAS / STING activation, this study reviews the latest research advances in the use of nanomaterials to modulate this signaling pathway. Based on the introduction of key cGAS-STING components and their activation mechanisms, this review focuses on nanomaterials that can mediate the corresponding agonists and effectively activate this signaling pathway. In addition, combination nanotherapies based on the activation of the cGAS-STING signaling pathway are also discussed, including emerging strategies combining nanoformulated agonists with chemotherapy, radiotherapy as well as immunomodulation in cancer therapy,.

The cGAS-STING pathway: a therapeutic target in diabetes and its complications

Diabetic wound healing (DWH) represents a major complication of diabetes where inflammation is a key impediment to proper healing. The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling pathway has emerged as a central mediator of inflammatory responses to cell stress and damage. However, the contribution of cGAS-STING activation to impaired healing in DWH remains understudied. In this review, we examine the evidence that cGAS-STING-driven inflammation is a critical factor underlying defective DWH. We summarize studies revealing upregulation of the cGAS-STING pathway in diabetic wounds and discuss how this exacerbates inflammation and senescence and disrupts cellular metabolism to block healing. Partial pharmaceutical inhibition of cGAS-STING has shown promise in damping inflammation and improving DWH in preclinical models. We highlight key knowledge gaps regarding cGAS-STING in DWH, including its relationships with endoplasmic reticulum stress and metal-ion signaling. Elucidating these mechanisms may unveil new therapeutic targets within the cGAS-STING pathway to improve healing outcomes in DWH. This review synthesizes current understanding of how cGAS-STING activation contributes to DWH pathology and proposes future research directions to exploit modulation of this pathway for therapeutic benefit.

Hierarchical-unlocking virus-esque NanoCRISPR precisely disrupts autocrine and paracrine pathway of VEGF for tumor inhibition and antiangiogenesis

Vascular endothelial growth factor (VEGF) not only serves as an autocrine survival factor for tumor cells themselves, but also stimulates angiogenesis by paracrine pathway. Strategies targeting VEGF holds tremendous potential for tumor therapy, however, agents targeting VEGF are limited by intolerable side effects, together with incomplete and temporary blocking of VEGF, resulting in unsatisfactory and unsustained therapeutic outcomes. Herein, hierarchical-unlocking virus-esque NanoCRISPR (HUNGER) is constructed for complete, permanent and efficient intracellular disruption of autocrine and paracrine pathway of VEGF, thereby eliciting notable tumor inhibition and antiangiogenesis. After intravenous administration, HUNGER exhibits prolonged blood circulation and hyaluronic acid-CD44 mediated tumor-targeting capability. Subsequently, when matrix metalloproteinase-2 is overexpressed in the tumor microenvironment, the PEG layer will be removed. The cell-penetrating peptide R8 endows HUNGER deep tumor penetration and specific cellular uptake. Upon cellular internalization, HUNGER undergoes hyaluronidase-triggered deshielding in lysosome, lysosomal escape is realized swiftly, and then the loaded CRISPR/Cas9 plasmid (>8 kb) is transported to nucleus efficiently. Consequentially, complete, permanent and efficient intracellular disruption of autocrine and paracrine pathway of VEGF ensures inhibition of angiogenesis and tumor growth with inappreciable toxicity. Overall, this work opens a brand-new avenue for anti-VEGF therapy and presents a feasible strategy for in vivo delivery of CRISPR/Cas9 system.

cGAS-STING signaling in the tumor microenvironment

The cGAS-STING signaling is an important pathway involved in the regulation of tumor microenvironment, which affects many cellular functions including immune activation. Its role in combating tumor progression is widely recognized, especially with its function in inducing innate and adaptive immune responses, on which many immunotherapies have been developed. However, a growing number of findings also suggest a diversity of its roles in shaping tumor microenvironment, including functions that promote tumor progression. Here, we summarize the functions of the cGAS-STING signaling in tumor microenvironment to maintain tumor survival and proliferation through facilitating the forming of an immunosuppressive tumor microenvironment and discuss the current advances of STING-related immunotherapies.

Ultra-efficient radio-immunotherapy for reprogramming the hypoxic and immunosuppressive tumor microenvironment with durable innate immune memory

Radiosensitization efficacy of conventional tumor radiosensitizers has been frequently limited by insufficient competence for tumor microenvironment (TME) regulation and unfavorable cellular uptake at biological barriers. Here, we reported an ultra-efficient radiotherapy (RT) strategy by synthesizing an extracellular vesicles (EVs)-encapsulated hollow MnO2 to load metformin (Met@HMnER). It demonstrated significant RT enhancement by morphological control of catalyst and cellular respiratory depression against conventional solid MnO2. Furthermore, the target-modified EVs clothing retains outstanding metformin loading capacity while endowing enhanced biological barrier penetration. A noticeably durable innate immune activation of NK cells was triggered with this nanoplatform via the cGAS-STING pathway. The enhanced immunocompetence was verified on distal metastasis and in-situ recurrence model in vivo, This work paved a new path for synergistic and robust innate immunity in clinical cancer treatment.

A STING pathway-activatable contrast agent for MRI-guided tumor immunoferroptosis synergistic therapy

The immunotherapy efficiency of stimulator of interferon genes (STING)-activatable drugs (e.g., 7-ethyl-10-hydroxycamptothecin, SN38) is limited by their non-specificity to tumor cells and the slow excretion of the DNA-containing exosomes from the treated cancer cells. The efficacy of tumor ferroptosis therapy is always limited by the elimination of lipid peroxides (LPO) by the pathways of glutathione peroxidase 4 (GPX4), dihydroorotate dehydrogenase (DHODH) and ferroptosis suppressor protein 1(FSP1). To solve these problems, in this study, we developed a STING pathway-activatable contrast agent (i.e., FeGd-HN@TA-Fe2+-SN38 nanoparticles) for magnetic resonance imaging (MRI)-guided tumor immunoferroptosis synergistic therapy. The remarkable in vivo MRI performance of FeGd-HN@TA-Fe2+-SN38 is attributed to its high accumulation at tumor location, the high relaxivities of FeGd-HN core, and the pH-sensitive TA-Fe2+-SN38 layer. The effectiveness and biosafety of the immunoferroptosis synergistic therapy induced by FeGd-HN@TA-Fe2+-SN38 are demonstrated by the in vivo investigations on the 4T1 tumor-bearing mice. The mechanisms of in vivo immunoferroptosis synergistic therapy by FeGd-HN@TA-Fe2+-SN38 are demonstrated by measurements of in vivo ROS, LPO, GPX4 and SLC7A11 levels, the intratumor matured DCs and CD8+ T cells, the protein expresion of STING and IRF-3, and the secretion of IFN-β and IFN-γ.

A Non-Nucleotide STING Agonist MSA-2 Synergized with Manganese in Enhancing STING Activation to Elicit Potent Anti-RNA Virus Activity in the Cells

Both Manganese (Mn2+) and MSA-2 can activate the downstream signal pathway through stimulator of interferon genes (STING) and induce the expression of type I interferon, which is important for hosts to protect against DNA viruses. However, its effect on RNA viruses remains unknown. In this study, we used Seneca Valley virus (SVV) as a model RNA virus to investigate the inhibitory effects of Mn2+ and MSA-2 on the virus replication in the porcine cells (PK-15 cells). The results showed that both MSA-2 and Mn2+ were able to inhibit the SVV replication in PK-15 cells. The combination of MAS-2 and Mn2+ could confer better protection against SVV. Further studies showed that MSA-2 and Mn2+ could activate TBK1, IRF3 and NFκB through STING and induce the expression of IFN-β, IL-6 and TNF-α. The present study confirmed that MSA-2 synergized with Mn2+ in STING activation to generate a better antiviral effect in vitro, which would be helpful for the further development of effective antiviral drugs in the future.

Stem Cell Therapy in Inflammatory Bowel Disease: A Review of Achievements and Challenges

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is a group of chronic inflammatory diseases of the gastrointestinal tract. Repeated inflammation can lead to complications, such as intestinal fistula, obstruction, perforation, and bleeding. Unfortunately, achieving durable remission and mucosal healing (MH) with current treatments is difficult. Stem cells (SCs) have the potential to modulate immunity, suppress inflammation, and have anti-apoptotic and pro-angiogenic effects, making them an ideal therapeutic strategy to target chronic inflammation and intestinal damage in IBD. In recent years, hematopoietic stem cells (HSCs) and adult mesenchymal stem cells (MSCs) have shown efficacy in treating IBD. In addition, numerous clinical trials have evaluated the efficiency of MSCs in treating the disease. This review summarizes the current research progress on the safety and efficacy of SC-based therapy for IBD in both preclinical models and clinical trials. We discuss potential mechanisms of SC therapy, including tissue repair, paracrine effects, and the promotion of angiogenesis, immune regulation, and anti-inflammatory effects. We also summarize current SC engineering strategies aimed at enhancing the immunosuppressive and regenerative capabilities of SCs for treating intestinal diseases. Additionally, we highlight current limitations and future perspectives of SC-related therapy for IBD.

STING agonist-loaded mesoporous manganese-silica nanoparticles for vaccine applications

Cyclic dinucleotides (CDNs), as one type of Stimulator of Interferon Genes (STING) pathway agonist, have shown promising results for eliciting immune responses against cancer and viral infection. However, the suboptimal drug-like properties of conventional CDNs, including their short in vivo half-life and poor cellular permeability, compromise their therapeutic efficacy. In this study, we have developed a manganese-silica nanoplatform (MnOx@HMSN) that enhances the adjuvant effects of CDN by achieving synergy with Mn2+ for vaccination against cancer and SARS-CoV-2. MnOx@HMSN with large mesopores were efficiently co-loaded with CDN and peptide/protein antigens. MnOx@HMSN(CDA) amplified the activation of the STING pathway and enhanced the production of type-I interferons and other proinflammatory cytokines from dendritic cells. MnOx@HMSN(CDA) carrying cancer neoantigens elicited robust antitumor T-cell immunity with therapeutic efficacy in two different murine tumor models. Furthermore, MnOx@HMSN(CDA) loaded with SARS-CoV-2 antigen achieved strong and durable (up to one year) humoral immune responses with neutralizing capability. These results demonstrate that MnOx@HMSN(CDA) is a versatile nanoplatform for vaccine applications.

Responsive manganese-based nanoplatform amplifying cGAS-STING activation for immunotherapy

BACKGROUND

The activation of the cyclic guanosine monophosphate-adenosine monophosphate synthase-stimulator of interferon genes (cGAS-STING) signaling pathway has attracted great attention for its ability to up-regulate innate immune response and thus enhance cancer immunotherapy. However, many STING agonists limit the further advancement of immunotherapy due to weak tumor responsiveness or low activation efficiency. The responsive and effective activation of cGAS-STING signaling in tumors is a highly challenging process.

METHODS

In this study, a manganese-based nanoplatform (MPCZ NPs) was constructed that could responsively and efficiently generate more manganese ions (Mn²⁺) and reactive oxygen species (ROS) to activate cGAS-STING signaling pathway. Briefly, manganese dioxide (MnO₂) was loaded with zinc protoporphyrin IX (ZPP) molecule and coated by polydopamine (PDA) embedded with NH₄HCO₃ to obtain MPCZ NPs. Additionally, MPCZ NPs were evaluated in vitro and in vivo for their antitumor effects by methyl thiazolyl tetrazolium (MTT) assay and TUNEL assays, respectively.

RESULTS

In this system, tumor responsiveness was achieved by exogenous (laser irradiation) and endogenous (high levels GSH) stimulation, which triggered the collapse or degradation of PDA and MnO₂. Moreover, the release of Mn²⁺ augmented the cGAS-STING signaling pathway and enhanced the conversion of hydrogen peroxide (H₂O₂) to hydroxyl radical (·OH) under NIR laser irradiation. Furthermore, the release of ZPP and the elimination of GSH by MPCZ NPs inhibited HO-1 activity and prevented ROS consumption, respectively.

CONCLUSIONS

This adopted open source and reduce expenditure strategy to effectively generate more ROS and Mn²⁺ to responsively activate cGAS-STING signaling pathway, providing a new strategy for improving immunotherapy.

Nanoparticle-Mediated STING Activation for Cancer Immunotherapy

As the first line of host defense against pathogenic infections, innate immunity plays a key role in antitumor immunotherapy. The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) (cGAS-STING) pathway has attracted much attention because of the secretion of various proinflammatory cytokines and chemokines. Many STING agonists have been identified and applied into preclinical or clinical trials for cancer immunotherapy. However, the fast excretion, low bioavailability, nonspecificity, and adverse effects of the small molecule STING agonists limit their therapeutic efficacy and in vivo application. Nanodelivery systems with appropriate size, charge, and surface modification are capable of addressing these dilemmas. In this review, the mechanism of the cGAS-STING pathway is discussed and the STING agonists, focusing on nanoparticle-mediated STING therapy and combined therapy for cancers, are summarized. Finally, the future direction and challenges of nano-STING therapy are expounded, emphasizing the pivotal scientific problems and technical bottlenecks and hoping to provide general guidance for its clinical application.

Advances of MnO2 nanomaterials as novel agonists for the development of cGAS-STING-mediated therapeutics

As an essential micronutrient, manganese plays an important role in the physiological process and immune process. In recent decades, cGAS-STING pathway, which can congenitally recognize exogenous and endogenous DNA for activation, has been widely reported to play critical roles in the innate immunity against some important diseases, such as infections and tumor. Manganese ion (Mn²⁺) has been recently proved to specifically bind with cGAS and activate cGAS-STING pathway as a potential cGAS agonist, however, is significantly restricted by the low stability of Mn²⁺ for further medical application. As one of the most stable forms of manganese, manganese dioxide (MnO₂) nanomaterials have been reported to show multiple promising functions, such as drug delivery, anti-tumor and anti-infection activities. More importantly, MnO₂ nanomaterials are also found to be a potential candidate as cGAS agonist by transforming into Mn²⁺, which indicates their potential for cGAS-STING regulations in different diseased conditions. In this review, we introduced the methods for the preparation of MnO₂ nanomaterials as well as their biological activities. Moreover, we emphatically introduced the cGAS-STING pathway and discussed the detailed mechanisms of MnO₂ nanomaterials for cGAS activation by converting into Mn²⁺. And we also discussed the application of MnO₂ nanomaterials for disease treatment by regulating cGAS-STING pathway, which might benefit the future development of novel cGAS-STING targeted treatments based on MnO₂ nanoplatforms.