Cancer Immunotherapy Based on Cell Membrane-Coated Nanocomposites Augmenting cGAS/STING Activation by Efferocytosis Blockade

Organelle-oriented nanomedicines in tumor therapy: Targeting, escaping, or collaborating?

Precise tumor therapy is essential for improving treatment specificity, enhancing efficacy, and minimizing side effects. Targeting organelles is a key strategy for achieving this goal and is a frontier research area attracting a considerable amount of attention. The concept of organelle targeting has a significant effect on the structural design of the nanodrugs employed. Most notably, the intricate interactions among different organelles in a tumor cell essentially create a unified system. Unfortunately, this aspect might have been somewhat overlooked when existing organelle-targeting nanodrugs were designed. In this review, we underscore the synergistic relationship among the various organelles and advocate for a holistic view of organelle-targeting design. Through the integration of biology and material science, recent advancements in organelle targeting, escaping, and collaborating are consolidated to offer fresh perspectives for the development of antitumor nanomedicines.

Nano-delivery of STING agonists: Unraveling the potential of immunotherapy

The cyclic GMP-AMP synthetase-interferon gene stimulator (cGAS-STING) pathway possesses tremendous potential in immune responses, viral defense, and anti-tumor treatment. Currently, an increasing number of nanocarriers are being engineered to convey STING agonists, with the goal of booSTING the conveying capacity of cGAS-STING agonists and augment the therapeutic potency of STING agonists. In this review, we explore the mechanisms of cGAS-STING activators, the application of different nanocarriers in the STING pathway, and the application of nanocarriers in anti-tumor therapy, antiviral therapy and autoimmune diseases. Additionally, we also discuss the adverse effects of STING pathway activation and the challenges encountered in nano delivery, we hope that future research will delve into the development of new nanocarriers and the clinical translation of nanocarriers in STING-mediated immunotherapy. STATEMENT OF SIGNIFICANCE: The cyclic GMP-AMP synthetase-interferon gene stimulator (cGAS-STING) pathway possesses tremendous potential in immune responses, viral defense, and anti-tumor treatment. In this review, we first explore the activation mechanism of cGAS-STING signal pathway and the diverse array of nanocarriers that have been employed in the context of the STING pathway, such as natural carrier, lipid nanoparticles, polymeric nanoparticles, and inorganic nanoparticles, highlighting their unique properties and the challenges they present in clinical applications. Furthermore, we discuss the research progress regarding nanocarriers in STING-mediated immunotherapy, such as the application of nanocarriers in anti-tumor therapy, antiviral therapy and autoimmune diseases therapy. Finally, the side effects of STING pathway activation and the issues encountered in nano delivery will be discussed, hoping that future research will delve into the development of new nanocarriers and the clinical translation of nanocarriers in STING-mediated immunotherapy.

H2O2 self-supplying nanoparticles for chemodynamic and synergistic photodynamic therapy to augment cGAS/STING activation

Triple negative breast cancer (TNBC) characterized by easy metastasis and poor prognosis is one of the most intractable malignancies. Immunotherapy, as one of the most promising treatments for TNBC, has limited efficacy due to the immunosuppressive tumor microenvironment (ITME). Herein, copper peroxide nanodots (CPN) and chlorin e6 (Ce6) were encapsulated in a liposome with the cinnamaldehyde dimer (CDC) to improve the ITME and enhance anti-tumor activity. To be specific, after endocytosis by cancer cells, Ce6-CPN@CDC released H2O2 and Cu2+ in the acidic tumor environment. Next, Cu2+ was reduced by GSH to Cu+, and Cu+ catalyzed H2O2 to produce ˙OH for chemodynamic therapy (CDT). Meanwhile, under near-infrared laser irradiation, singlet oxygen (1O2) can be generated from the released Ce6, exerting a robust photodynamic anticancer effect. In addition, the high ROS-induced ICD and direct DNA damage activated the cGAS-STING pathway, which significantly improved the ITME to amplify the immunostimulatory effect. In vitro and in vivo studies showed that the Ce6-CPN@CDC nanoparticle could realize effective tumor inhibition with minimal toxic side effects. Together, Ce6-CPN@CDC provides a paradigm for combining PDT and CDT to activate immunotherapy and provides a new strategy to improve the efficacy of multimodal synergistic therapy for TNBC.

Enhancing nano-immunotherapy of cancer through cGAS-STING pathway modulation

Activation of the cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)-stimulator of interferon genes (STING) pathway plays a critical role in cancer immunotherapy due to the secretion of multiple pro-inflammatory cytokines and chemokines. Numerous cGAS-STING agonists have been developed for preclinical and clinical trials in tumor immunity. However, several obstacles, such as agonist molecules requiring multiple doses, rapid degradation and poor targeting, weaken STING activation at the tumor site. The advancement of nanotechnology provides an optimized platform for the clinical application of STING agonists. In this review, we summarize events of cGAS-STING pathway activation, the dilemma of delivering STING agonists, and recent advances in the nano-delivery of cGAS-STING agonist formulations for enhancing tumor immunity. Furthermore, we address the future challenges associated with STING-based therapies and offer insights to guide subsequent clinical applications.

Ta4C3 MXene Slows Progression of Fatty Liver Disease through Its Anti-Inflammatory and ROS-Scavenging Effects

Treating metabolic dysfunction-associated fatty liver disease (MAFLD) and reducing the occurrence of MAFLD-associated liver cancer remain challenging. Two-dimensional (2D) tantalum carbide (Ta4C3) MXene nanozymes (MXenzymes) exhibit antioxidant and anti-inflammatory activities and have thus attracted considerable attention in the fields of oncology and engineering. However, the potential mechanism of action and bioactive properties of Ta4C3 in MAFLD remain uncertain. In our study, Ta4C3 not only inhibited lipid accumulation and disrupted lipid metabolism in hepatocytes but also reduced cell death caused by fatty acids by decreasing intracellular reactive oxygen species (ROS) levels, which significantly promoted the polarization of M1 macrophages to M2 macrophages by alleviating oxidative stress and further suppressing inflammatory factor expression. In mice fed a methionine-choline-deficient (MCD) diet, Ta4C3 reduced lipid accumulation, the infiltration of inflammatory cells, and liver cell apoptosis by modulating the cellular microenvironment through its anti-inflammatory and antioxidant properties. Therefore, Ta4C3 can be used as a multifunctional bioactive material to alleviate hepatic steatosis and inflammation in individuals with MAFLD/metabolic dysfunction-associated steatohepatitis (MASH) because of its robust antioxidant and anti-inflammatory effects.

Cell membrane-camouflaged nanocarriers: A cutting-edge biomimetic technology to develop cancer immunotherapy

The development and growth of many diseases are significantly influenced by immune dysregulation. Similarly, uncontrolled tumor growth occurs in cancer because the immune system is unable to identify and eradicate cancer cells. Therefore, to address this issue, cancer immunotherapy plays a crucial role in detecting tumors and inhibiting their growth. This immune-oncotherapy has gained significant interest over the last decade because of its relevant success in biomedical applications. The fundamental goal of immunotherapy in the war against cancer is to develop potent immunotherapies that have minimal side effects and excellent tumor selectivity. To develop these characteristics, nanotechnology offered promising opportunities for cancer immunotherapy. Cell membrane-coated nanoparticles (CMNPs) have recently evolved, which has a tremendous advantage over other nanoparticles (NPs). The CMNPs can be formed by wrapping cell membranes, which can camouflage the specific cell type, allowing these NPs to survive like "self" during blood circulation and escape immune cell capture. These provide NPs with increased biocompatibility, minimal immunogenicity, longer circulation, and targeted tumor therapy. These advantages have made CMNPs a potential delivery vehicle for immunostimulatory drugs, which can induce immunological responses and lead to cancer immunotherapy. Surface modification of CMNPs using cutting-edge genetic engineering techniques revolutionizes cancer immunotherapy to produce new nano-formulations with greater effectiveness. In this review, we briefly discuss the relationship between cancer and the immune system, various techniques of CMNPs synthesis, and the use of naturally occurring and genetically modified CMNPs for cancer immunotherapy.

Dual Metal Nanoflower Oxygen Pump Microneedles Based on Cuproptosis and STING Pathway Activation for Cancer Immunotherapy

Immunotherapy is a promising new approach for tumor treatment. However, its clinical application is hindered by insufficient immunogenicity, hypoxia, and immunosuppressive tumor microenvironment (TME). Here, oxygen pump microneedles (OPMNs) loaded with zinc-doped copper sulfide nanoflowers (ZCS NFs) and PD-L1 small interfering RNA (siPD-L1) (OPMNs-ZCS@siPD-L1) are developed for boosting tumor immunotherapy. OPMN-ZCS@siPD-L1 enhances tumor immunogenicity through ZCS NFs by inducing cuproptosis, reverses TME through siPD-L1, and promotes drug penetration, and ameliorates hypoxia through oxygen bubbles. More importantly, cuproptosis-induced mitochondrial DNA (mtDNA) together with Zn2+ co-activate the STING pathway, triggering a robust immune response. OPMN-ZCS@siPD-L1 increases the sensitivity to cuproptosis and induces immunogenic cell death (ICD) in vivo and in vitro, which significantly inhibits tumor progression and metastasis. The novel strategy of "increasing the throttle" (cuproptopsis-mediated STING activation & ICD effect) combined with "releasing the brake" (PD-L1 inhibition & hypoxia improvement) provides a new approach for enhancing percutaneous tumor immunotherapy.

Less is More: Biomimetic Hybrid Membrane Nanocarriers for Highly Efficient Tumor Targeted Drug Delivery

Biomimetic camouflaged nanocarriers coated with cancer cell membranes (CCMs) have attracted considerable research attention for drug delivery application. CCM-camouflaged nanocarriers have inherent tumor-homologous targeting ability. However, they enter cancer cells via endocytosis, which is not efficient for drug delivery. Switching the internalization mechanism to membrane fusion may enhance their delivery efficiency. In this study, an innovative biomimetic-targeting nanocarrier is designed by hybridizing CCMs with pH-sensitive liposomes (1,2-dioleoyl-sn-glycero-3-phosphoethanolamine liposomes, DOPE-Lipo), named as CCMpHD. The presence of CCMs makes the nanocarriers capable of homologous targeting, and the DOPE-Lipo hybrid allows the nanocarriers to achieve efficient internalization via membrane fusion. Notably, the cellular uptake of CCMpHD is significantly higher than that of the CCMs. The most efficient delivery is achieved with 1/10 CCMs, which requires remarkably less cell membranes. Doxorubicin (DOX) is used as a model drug to characterize the homologous targeting drug delivery properties of the hybrid nanocarriers. Both in vitro and in vivo experiments demonstrated that the nanocarriers exhibited satisfactory biosafety and enhanced tumor-targeted delivery. With enhanced delivery efficiency whilst requiring fewer CCMs, these hybrid membrane nanocarriers provides a new strategy for CCM-based drug delivery in cancer treatment.

Nanomedicines harnessing cGAS-STING pathway: sparking immune revitalization to transform 'cold' tumors into 'hot' tumors

cGAS-STING pathway stands at the forefront of innate immunity and plays a critical role in regulating adaptive immune responses, making it as a key orchestrator of anti-tumor immunity. Despite the great potential, clinical outcomes with cGAS-STING activators have been disappointing due to their unfavorable in vivo fate, signaling an urgent need for innovative solutions to bridge the gap in clinical translation. Recent advancements in nanotechnology have propelled cGAS-STING-targeting nanomedicines to the cutting-edge of cancer therapy, leveraging precise drug delivery systems and multifunctional platforms to achieve remarkable region-specific biodistribution and potent therapeutic efficacy. In this review, we provide an in-depth exploration of the molecular mechanisms that govern cGAS-STING signaling and its potential to dynamically modulate the anti-tumor immune cycle. We subsequently introduced several investigational cGAS-STING-dependent anti-tumor agents and summarized their clinical trial progress. Additionally, we provided a comprehensive review of the unique advantages of cGAS-STING-targeted nanomedicines, highlighting the transformative potential of nanotechnology in this field. Furthermore, we comprehensively reviewed and comparatively analyzed the latest breakthroughs cGAS-STING-targeting nanomedicine, focusing on strategies that induce cytosolic DNA generation via exogenous DNA delivery, chemotherapy, radiotherapy, or dynamic therapies, as well as the nanodelivery of STING agonists. Lastly, we discuss the future prospects and challenges in cGAS-STING-targeting nanomedicine development, offering new insights to bridge the gap between mechanistic research and drug development, thereby opening new pathways in cancer treatment.

Zinc-based radioenhancers to activate tumor radioimmunotherapy by PD-L1 and cGAS-STING pathway

Radiotherapy and immunotherapy have already become the primary form of treatment for non-small-cell lung cancer (NSCLC), but are limited by high radiotherapy dose and low immune response rate. Herein, a multi-pronged strategy using a radio-immuno-enhancer (ZnO-Au@mSiO2) is developed by inducing tumor cells apoptosis and reprograming the immunosuppressive tumor microenvironment (TME). The radio-immuno-enhancer employed Au as a radiosensitizer, transition Zn ions as immune activators, which not only tremendously enhances the anti-proliferative activity of radiotherapy toward cancer cells, but also activates the immune response with multi-targets to let "exhausted" T cells "back to life" by triggering immunogenic cell death (ICD), immune checkpoint blockade (ICB) that target PD-1/PD-L1 and cGAS-STING under X-ray irradiation with a low dosage. The in vivo results demonstrate desirable antitumor and immunogenic effects of radio-immuno-enhancer-mediated immune activation by increasing the ratio of cytotoxic T cells (CTLs) and helper T cells. This work provides a feasible approach for future development of effective transition metal ion-activated radio-immunotherapeutic agents.

A Multifunctional Exosome with Dual Homeostasis Disruption Augments cGAS-STING-Mediated Tumor Immunotherapy by Boosting Ferroptosis

Ferroptosis has shown great potential in activating antitumor immunity. However, the cunning tumor cells can evade ferroptosis by increasing the efflux of iron and promoting the production of the reductant glutathione to mitigate oxidative stress. Herein, a multifunctional exosome loaded with manganese-doped iron oxide nanoparticles (MnIO), GW4869, and l-buthionine sulfoximine (BSO) is developed to disrupt the iron metabolism homeostasis and redox homeostasis to enhance tumor immunotherapy. The efficient transport of MnIO by exosomes and the inhibition of iron exocytosis by GW4869 led to a high retention of up to 29.57% ID/g for iron in the tumors. Such a high retention of iron, in combination with the BSO-induced disruption of the redox homeostasis, effectively promotes the ferroptosis of tumor cells. Consequently, the multifunctional exosomes that noticeably enhance ferroptosis by dual homeostasis disruption provoke the cGAS-STING-based antitumor immune response and effectively suppress tumor growth and lung metastasis in orthotopic breast cancer.

Connexin 43 Deficiency Confers Resistance to Immunotherapy in Lung Cancer via Inhibition of the Cyclic GMP-AMP Synthase-Stimulator of Interferon Genes Pathway

Immune checkpoint inhibitors (ICIs), especially PD-1 inhibitors, are among the first-line therapeutic drugs for the treatment of advanced non-small cell lung cancer (NSCLC). However, most patients are not sensitive to PD-1 inhibitors, and prolonged exposure can lead to acquired resistance. Thus, it is urgent to elucidate the mechanism underlying the resistance of NSCLC to ICIs. Connexin 43 (Cx43) is a gap junction (GJ) protein that is important in therapeutic efficacy to ICIs. In this study, we observed that Cx43 in murine Lewis lung carcinoma (LLC) cells mediated cyclic GMP-AMP (cGAMP) transfer to macrophages. Knockdown of Cx43 reduced T-cell activation, leading to decreased sensitivity of LLC cells to anti-PD-1 therapy. The mechanism might be that knockdown of Cx43 in LLC cells promotes macrophages differentiation into pro-tumour M2 type (TAM), thus activating the STING pathway in macrophages. These findings indicate that downregulation of Cx43 in LLC cells leads to immunotherapy resistance by negatively regulating the cGAS-STING pathway in macrophages. Therefore, Cx43/GJ-mediated signal transmission between lung cancer cells and macrophages provides new insights for increasing immunotherapy sensitivity in NSCLC.

Mechanism of Efferocytosis in Determining Ischaemic Stroke Resolution-Diving into Microglia/Macrophage Functions and Therapeutic Modality

After ischaemic cerebral vascular injury, efferocytosis-a process known as the efficient clearance of apoptotic cells (ACs) by various phagocytes in both physiological and pathological states-is crucial for maintaining central nervous system (CNS) homeostasis and regaining prognosis. The mechanisms of efferocytosis in ischaemic stroke and its influence on preventing inflammation progression from secondary injury were still not fully understood, despite the fact that the fundamental process of efferocytosis has been described in a series of phases, including AC recognition, phagocyte engulfment, and subsequent degradation. The genetic reprogramming of macrophages and brain-resident microglia after an ischaemic stroke has been equated by some researchers to that of the peripheral blood and brain. Based on previous studies, some molecules, such as signal transducer and activator of transcription 6 (STAT6), peroxisome proliferator-activated receptor γ (PPARG), CD300A, and sigma non-opioid intracellular receptor 1 (SIGMAR1), were discovered to be largely associated with aspects of apoptotic cell elimination and accompanying neuroinflammation, such as inflammatory cytokine release, phenotype transformation, and suppressing of antigen presentation. Exacerbated stroke outcomes are brought on by defective efferocytosis and improper modulation of pertinent signalling pathways in blood-borne macrophages and brain microglia, which also results in subsequent tissue inflammatory damage. This review focuses on recent researches which contain a number of recently discovered mechanisms, such as studies on the relationship between benign efferocytosis and the regulation of inflammation in ischaemic stroke, the roles of some risk factors in disease progression, and current immune approaches that aim to promote efferocytosis to treat some autoimmune diseases. Understanding these pathways provides insight into novel pathophysiological processes and fresh characteristics, which can be used to build cerebral ischaemia targeting techniques.

Study of Biological Effects Induced in Solid Tumors by Shortened-Duration Thermal Ablation Using High-Intensity Focused Ultrasound

The HIFU ablation technique is limited by the long duration of the procedure, which results from the large difference between the size of the HIFU beam's focus and the tumor size. Ablation of large tumors requires treating them with a sequence of single HIFU beams, with a specific time interval in-between. The aim of this study was to evaluate the biological effects induced in a malignant solid tumor of the rat mammary gland, implanted in adult Wistar rats, during HIFU treatment according to a new ablation plan which allowed researchers to significantly shorten the duration of the procedure. We used a custom, automated, ultrasound imaging-guided HIFU ablation device. Tumors with a 1 mm thickness margin of healthy tissue were subjected to HIFU. Three days later, the animals were sacrificed, and the HIFU-treated tissues were harvested. The biological effects were studied, employing morphological, histological, immunohistochemical, and ultrastructural techniques. Massive cell death, hemorrhages, tissue loss, influx of immune cells, and induction of pro-inflammatory cytokines were observed in the HIFU-treated tumors. No damage to healthy tissues was observed in the area surrounding the safety margin. These results confirmed the efficacy of the proposed shortened duration of the HIFU ablation procedure and its potential for the treatment of solid tumors.

Advanced Strategies for Strengthening the Immune Activation Effect of Traditional Antitumor Therapies

The utilization of traditional therapies (TTS), such as chemotherapy, reactive oxygen species-based therapy, and thermotherapy, to induce immunogenic cell death (ICD) in tumor cells has emerged as a promising strategy for the activation of the antitumor immune response. However, the limited effectiveness of most TTS in inducing the ICD effect of tumors hinders their applications in combination with immunotherapy. To address this challenge, various intelligent strategies have been proposed to strengthen the immune activation effect of these TTS, and then achieve synergistic antitumor efficacy with immunotherapy. These strategies primarily focus on augmenting the tumor ICD effect or facilitating the antigen (released by the ICD tumor cells) presentation process during TTS, and they are systematically summarized in this review. Finally, the existing bottlenecks and prospects of TTS in the application of tumor immune regulation are also discussed.

NIR Absorbing Organic Chromophores Combination with NSAIDs for Remodeling of the Inflammatory Microenvironment to Amplify Tumor Ferroptosis-Photothermal Synergistic Therapy

Photothermal therapy has emerged as a promising approach for cancer treatment, which can cause ferroptosis to enhance immunotherapeutic efficacy. However, excessively generated immunogenicity will induce serious inflammatory response syndrome, resulting in a discounted therapeutic effect. Herein, a kind of NIR absorption small organic chromophore nanoparticles (TTHM NPs) with high photothermal conversion efficiency (68.33%) is developed, which can induce mitochondria dysfunction, generate mitochondrial superoxide, and following ferroptosis. TTHM NPs-based photothermal therapy is combined with Sulfasalazine (SUZ), a kind of nonsteroidal anti-inflammatory drugs, to weaken inflammation and promote ferroptosis through suppressing glutamate/cystine (Glu/Cys) antiporter system Xc- (xCT). Additionally, the combination of SUZ with PTT can induce immunogenic cell death (ICD), followed by promoting the maturation of DCs and the attraction of CD8+ T cell, which will secrete IFN-γ and trigger self-amplified ferroptosis via inhibiting xCT and simulating Acyl-CoA synthetase long-chain family member 4 (ACSL4). Moreover, the in vivo results demonstrate that this combination therapy can suppress the expression of inflammatory factors, enhance dendritic cell activation, facilitate T-cell infiltration, and realize effective thermal elimination of primary tumors and distant tumors. In general, this work provides an excellent example of combined medication and stimulates new thinking about onco-therapy and inflammatory response.

Components, Formulations, Deliveries, and Combinations of Tumor Vaccines

Tumor vaccines, an important part of immunotherapy, prevent cancer or kill existing tumor cells by activating or restoring the body's own immune system. Currently, various formulations of tumor vaccines have been developed, including cell vaccines, tumor cell membrane vaccines, tumor DNA vaccines, tumor mRNA vaccines, tumor polypeptide vaccines, virus-vectored tumor vaccines, and tumor-in-situ vaccines. There are also multiple delivery systems for tumor vaccines, such as liposomes, cell membrane vesicles, viruses, exosomes, and emulsions. In addition, to decrease the risk of tumor immune escape and immune tolerance that may exist with a single tumor vaccine, combination therapy of tumor vaccines with radiotherapy, chemotherapy, immune checkpoint inhibitors, cytokines, CAR-T therapy, or photoimmunotherapy is an effective strategy. Given the critical role of tumor vaccines in immunotherapy, here, we look back to the history of tumor vaccines, and we discuss the antigens, adjuvants, formulations, delivery systems, mechanisms, combination therapy, and future directions of tumor vaccines.

Improved Immune Response for Colorectal Cancer Therapy Triggered by Multifunctional Nanocomposites with Self-Amplifying Antitumor Ferroptosis

Ferroptosis, as a type of regulated cell death, can trigger the release of damage-associated molecular patterns from cancer cells and lead to the enhancement of immune recognition. Fenton reaction-mediated chemodynamic therapy could initiate ferroptosis by generating lipid peroxides, but its efficiency would be greatly restricted by the insufficient H2O2 and antioxidant system within the tumor. Herein, this work reports the successful preparation of H2O2 self-supplied and glutathione (GSH)-depletion therapeutic nanocomposites (Cu2O@Au) through in situ growth of Au nanoparticles on the surface of cuprous oxide (Cu2O) nanospheres. Upon delivery into cancer cells, the released Cu2O could consume endogenous H2S within colorectal cancer cells to form Cu31S16 nanoparticles, while the released Au NPs could catalyze glucose to generate H2O2 and gluconic acid. The self-supplying endogenous H2O2 and lower acidity could amplify the Cu ion-induced Fenton-like reaction. Meanwhile, the consumption of glucose would reduce GSH generation by disrupting the pentose phosphate pathway. Additionally, the Cu2+/Cu+ catalytic cycle promotes the depletion of GSH, leading to lipid peroxide accumulation and ferroptosis. It was found that the onset of ferroptosis triggered by Cu2O@Au could initiate immunologic cell death, promote dendritic cell maturation and T-cell infiltration, and finally enhance the antitumor efficacy of the PD-L1 antibody. In summary, this collaborative action produces a remarkable antitumor effect, which provides a promising treatment strategy for colorectal cancer.

Liposome-coated nanoparticle triggers prostate cancer ferroptosis through synergetic chemodynamic-gas therapy

Ferroptosis has attracted much attention for tumor treatment. It has been recently identified that castration-resistant prostate cancer (CRPC) is vulnerable to ferroptosis inducers. Notably, chemodynamic therapy (CDT), triggered by metal ions, could easily induce ferroptosis via a Fenton/Fenton-like reaction, but its efficiency was highly dependent on the intracellular H2O2 concentration, posing significant changes for its clinical translation. Herein, we attached glucose oxidase (GOx) onto the surface of manganese sulfide (MnS) and developed therapeutic nanocomposites (Lpo@MnS-GOx) after encapsulating with liposome. Upon internalization by cancer cells, the released GOx could transform glucose into gluconic acid (GA) and H2O2. Notably, the generated GA stimulates the degradation of MnS, followed by the promotion of the release of H2S and Mn2+, whereas the produced H2O2 can amplify the Fenton-like response initiated by Mn2+. The enhanced CDT combined with the gas therapy effect could simultaneously promote the accumulation of reactive oxygen species and finally induce ferroptosis and exhibit an excellent anti-tumor effect. Consequently, these Lpo@MnS-GOx NPs with enhanced ferroptosis-induced effect will find great potential for CRPC cancer treatment.

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.

At the Crossroads of the cGAS-cGAMP-STING Pathway and the DNA Damage Response: Implications for Cancer Progression and Treatment

The evolutionary conserved DNA-sensing cGAS-STING innate immunity pathway represents one of the most important cytosolic DNA-sensing systems that is activated in response to viral invasion and/or damage to the integrity of the nuclear envelope. The key outcome of this pathway is the production of interferon, which subsequently stimulates the transcription of hundreds of genes. In oncology, the situation is complex because this pathway may serve either anti- or pro-oncogenic roles, depending on context. The prevailing understanding is that when the innate immune response is activated by sensing cytosolic DNA, such as DNA released from ruptured micronuclei, it results in the production of interferon, which attracts cytotoxic cells to destroy tumors. However, in tumor cells that have adjusted to significant chromosomal instability, particularly in relapsed, treatment-resistant cancers, the cGAS-STING pathway often supports cancer progression, fostering the epithelial-to-mesenchymal transition (EMT). Here, we review this intricate pathway in terms of its association with cancer progression, giving special attention to pancreatic ductal adenocarcinoma and gliomas. As the development of new cGAS-STING-modulating small molecules and immunotherapies such as oncolytic viruses involves serious challenges, we highlight several recent fundamental discoveries, such as the proton-channeling function of STING. These discoveries may serve as guiding lights for potential pharmacological advancements.