Intracavitary Spraying of Nanoregulator-Encased Hydrogel Modulates Cholesterol Metabolism of Glioma-Supportive Macrophage for Postoperative Glioblastoma Immunotherapy

Breaking the barriers in effective and safe Toll-like receptor stimulation via nano-immunomodulators for potent cancer immunotherapy

Immunotherapy is an emerging strategy that awakens the intrinsic immune system for cancer treatment. Generally, successful immunotherapy of malignant tumours relies on the effective production of tumour-associated antigens and their lymph node delivery, antigen processing and presentation for T-cell activation, and the dismantling of the immunosuppressive tumour microenvironment. Toll-like receptor (TLR) agonists are potent stimulants in cancer immunotherapy, which can directly activate antigen-presenting cells (APCs) and further induce T cell activation for antitumour immune response and convert immunosuppressive tumour microenvironment to an immunogenic one for cooperative tumour ablation. However, TLR agonists for effective cancer immunotherapy have encountered essential challenges, such as insufficient immune activation and systemic side effects. In recent years, nano-immunomodulators with TLR agonists have been employed for tumour- and/or lymph node-targeted immune activation to improve the antitumour immune response and alleviate their systemic toxicities, providing a promising strategy for enhanced cancer immunotherapy. Herein, we introduce the recent progress in developing various TLR nano-immunomodulators for cancer immunotherapy via APC activation and tumour microenvironment remodelling. Upon elucidating the rational design principles of nano-immunomodulators, we elucidate the advancement of TLR nanoagonists to break the barriers in effective and safe Toll-like receptor stimulation for potent cancer immunotherapy.

Targeting the glioblastoma resection margin with locoregional nanotechnologies

Surgical resection is the first stage of treatment for patients diagnosed with resectable glioblastoma and is followed by a combination of adjuvant radiotherapy and systemic single-agent chemotherapy, which is typically commenced 4-6 weeks after surgery. This delay creates an interval during which residual tumour cells residing in the resection margin can undergo uninhibited proliferation and further invasion, even immediately after surgery, thus limiting the effectiveness of adjuvant therapies. Recognition of the postsurgical resection margin and peri-marginal zones as important anatomical clinical targets and the need to rethink current strategies can galvanize opportunities for local, intraoperative approaches, while also generating a new landscape of innovative treatment modalities. In this Perspective, we discuss opportunities and challenges for developing locoregional therapeutic strategies to target the glioblastoma resection margin as well as emerging opportunities offered by nanotechnology in this clinically transformative setting. We also discuss how persistent barriers to clinical translation can be overcome to offer a potential path forward towards broader acceptability of such advanced technologies.

Biomimetic Hybrid PROTAC Nanovesicles Block Multiple DNA Repair Pathways to Overcome Temozolomide Resistance Against Orthotopic Glioblastoma

Glioblastoma (GBM) remains one of the deadliest forms of cancer due to its high rates of postoperative recurrence and resistance to treatment. Temozolomide (TMZ) is the standard chemotherapy for GBM. However, the therapeutic efficacy of TMZ is significantly compromised by the activation of various intracellular DNA repair mechanisms that facilitate TMZ resistance. Herein, the upregulation of bromodomain-containing protein 4 (BRD4) expression is demonstrated to be a key contributor to TMZ resistance in GBM. To address this challenge, a biomimetic hybrid PROteolysis TArgeting Chimeras (PROTAC) liposome delivery system (M@TP) is developed. This system efficiently penetrates the blood-brain barrier (BBB) and specifically targets GBM cells through homotypic recognition. Once within TMZ-resistant GBM cells, the released PROTAC from M@TP can specifically degrade BRD4, effectively inhibiting multiple DNA repair pathways and restoring sensitivity to TMZ treatment. In vivo, studies showed that M@TP demonstrated significant efficacy in suppressing tumor growth in both TMZ-resistant and postoperative GBM, with prolonged mouse survival times. These findings highlight the potential of M@TP as a promising strategy to overcome TMZ resistance and improve therapeutic outcomes in GBM.

Cholesterol effects on the tumor immune microenvironment: from fundamental concepts to mechanisms and implications

In many cancers, the tumor microenvironment is enriched with cholesterol due to increased biosynthesis and uptake by cancer cells, resulting in the accumulation of cholesterol, cholesterol esters, oxysterols and other metabolites with various functions. These molecules serve as structural components, energy sources and intracellular signaling mediators, while their toxic by-products are secreted to suppress anti-tumor immune activity and prevent lipid peroxidation that could induce cancer cell apoptosis. Immune cells in the tumor microenvironment also contribute to cholesterol dynamics. Tumor-associated macrophages (TAMs) release cholesterol to support tumor cell metabolism, while myeloid-derived suppressor cells (MDSCs) also release cholesterol and consume essential metabolites such as L-arginine, which impairs T-cell proliferation and activation. Elevated cholesterol in dendritic cells impairs migration and tumor antigen presentation and, in lymphocytes, favors the development of a regulatory T cells (Treg) phenotype and inhibits the release of antitumor cytokines, further weakening the immune response. These findings suggest that targeting cholesterol metabolism is a promising strategy for cancer treatment, improving the efficacy of immune checkpoint blockade (ICB) therapies. In this manuscript, the molecular mechanisms underlying the effects of cholesterol on the tumor immune landscape are reviewed and the potential of cholesterol-lowering drugs to enhance antitumor immune responses is explored.

Engineered Bacterial Outer Membrane Vesicles-Based Doxorubicin and CD47-siRNA Co-Delivery Nanoplatform Overcomes Immune Resistance to Potentiate the Immunotherapy of Glioblastoma

Apart from the blood-brain barrier (BBB), the efficacy of immunotherapy for glioblastoma (GBM) is limited by the presence of intrinsic and adaptive immune resistance, implying that co-delivery of various immunotherapeutic agents or simultaneous regulation of different cells is urgently needed. Bacterial outer membrane vesicles (OMVs) offer a unique advantage in the treatment of GBM, owing to their multifunctional properties as carriers and immune adjuvants and their ability to cross the BBB. However, traditional OMVs can lead to toxic side effects and disruption of tight junctions in the BBB. Therefore, to enhance the in vivo safety and targeting capability of OMVs, we introduced engineered OMVs to reduce toxicity and further constructed a modularly assembled nanoplatform by performing simple peptide modifications. This nanoplatform demonstrates satisfactory biosafety and is able to continuously cross the BBB and target GBM with the assistance of Angiopep-2. Subsequently, immunogenic substances on OMVs, along with carried small-interfering RNA (siRNA) and doxorubicin, can promote and enhance the reprogramming and phagocytic abilities of macrophages and microglia, respectively, and increase the immunogenicity of GBM, ultimately overcoming GBM immune resistance to enhance the efficacy of immunotherapy. This OMVs-based nanoplatform provides a new paradigm and insights into the development of immunotherapy for GBM.

Metabolic cross-talk between glioblastoma and glioblastoma-associated microglia/macrophages: From basic insights to therapeutic strategies

Glioblastoma (GBM), a highly malignant "cold" tumor of the central nervous system, is characterized by its ability to remodel the GBM immune microenvironment (GME), leading to significant resistance to immunotherapy. GBM-associated microglia/macrophages (GAMs) are essential components of the GME. Targeting GAMs has emerged as a promising strategy against GBM. However, their highly immunosuppressive nature contributes to GBM progression and drug resistance, significantly impeding anti-GBM immunotherapy. Accumulating evidence suggests that metabolic reprogramming accompanies GBM progression and GAM polarization, which are in turn driven by specific metabolic abnormalities and altered cellular signaling pathways. Importantly, metabolic crosstalk between GBM and GAMs further promotes tumor progression. Clarifying and disrupting this metabolic crosstalk is expected to enhance the antitumor phenotype of GAMs and inhibit GBM malignant progression. This review explores metabolism-based interregulation between GBM and GAMs and summarizes recent therapeutic strategies targeting this crosstalk, offering new insights into GBM immunotherapy.

Myeloid cells: key players in tumor microenvironments

Cancer is the result of evolving crosstalk between neoplastic cell and its immune microenvironment. In recent years, immune therapeutics targeting T lymphocytes, such as immune checkpoint blockade (ICB) and CAR-T, have made significant progress in cancer treatment and validated targeting immune cells as a promising approach to fight human cancers. However, responsiveness to the current immune therapeutic agents is limited to only a small proportion of solid cancer patients. As major components of most solid tumors, myeloid cells played critical roles in regulating the initiation and sustentation of adaptive immunity, thus determining tumor progression as well as therapeutic responses. In this review, we discuss emerging data on the diverse functions of myeloid cells in tumor progression through their direct effects or interactions with other immune cells. We explain how different metabolic reprogramming impacts the characteristics and functions of tumor myeloid cells, and discuss recent progress in revealing different mechanisms-chemotaxis, proliferation, survival, and alternative sources-involved in the infiltration and accumulation of myeloid cells within tumors. Further understanding of the function and regulation of myeloid cells is important for the development of novel strategies for therapeutic exploitation in cancer.

Nanomaterial-enabled metabolic reprogramming strategies for boosting antitumor immunity

Immunotherapy has become a crucial strategy in cancer treatment, but its effectiveness is often constrained. Most cancer immunotherapies focus on stimulating T-cell-mediated immunity by driving the cancer-immunity cycle, which includes tumor antigen release, antigen presentation, T cell activation, infiltration, and tumor cell killing. However, metabolism reprogramming in the tumor microenvironment (TME) supports the viability of cancer cells and inhibits the function of immune cells within this cycle, presenting clinical challenges. The distinct metabolic needs of tumor cells and immune cells require precise and selective metabolic interventions to maximize therapeutic outcomes while minimizing adverse effects. Recent advances in nanotherapeutics offer a promising approach to target tumor metabolism reprogramming and enhance the cancer-immunity cycle through tailored metabolic modulation. In this review, we explore cutting-edge nanomaterial strategies for modulating tumor metabolism to improve therapeutic outcomes. We review the design principles of nanoplatforms for immunometabolic modulation, key metabolic pathways and their regulation, recent advances in targeting these pathways for the cancer-immunity cycle enhancement, and future prospects for next-generation metabolic nanomodulators in cancer immunotherapy. We expect that emerging immunometabolic modulatory nanotechnology will establish a new frontier in cancer immunotherapy in the near future.

The High-Affinity IL-2 Receptor Affects White Matter Damage after Cerebral Ischemia by Regulating CD8 + T Lymphocyte Differentiation

IL-2/IL-2R inhibition improved the prognosis of ischemic stroke by regulating T cells, while the respective contribution of T cells with high/medium/low-affinity IL-2 receptors remained unclear. Single-cell RNA sequencing data of ischemic brain tissue revealed that most of the high-affinity IL-2R would be expressed by CD8 + T cells, especially by a highly-proliferative subset. Interestingly, only the CD8 + T cells with high-affinity IL-2R infiltrated ischemic brain tissues, highly expressing 32 genes (including Cdc20, Cdca3/5, and Asns) and activating 7 signaling pathways (including the interferon-alpha response pathway, a key mediator in the proliferation, migration, and cytotoxicity of CD8 + T cells). Its interaction with endothelial cells and the ligand-receptor interaction analysis also suggested an augmented brain infiltration after cerebral ischemia. In IL-2Rα KO mice, who would have no high- or low-affinity IL-2R in CD8 + T cells, the RNA-seq, qPCR, immunofluorescence, and multiplex assays found that the expression of CD8b, CD122, CD132, and Vcam-1 was upregulated in the acute phase of cerebral ischemia, with decreasing H2-k1 positive cells and increasing Vcam-1 and CD8b positive cells in brain tissue. However, inflammation pathways in brain were inhibited and peripheral inflammatory cytokine levels were reduced, indicating that CD8 + T cells changed into an anti-inflammatory phenotype. The IL-2Rα KO mice after cerebral ischemia also performed better in behavioral tests and had more favorable results in diffusion tensor imaging, electrophysiology, and MBP testing. Our findings suggested that the CD8 + T cells with high-affinity IL-2R, as well as IL-2Rα, might be targeted to improve the clinical management of ischemic stroke.

Engineered biomimetic cisplatin-polyphenol nanocomplex for chemo-immunotherapy of glioblastoma by inducing pyroptosis

Glioblastoma multiforme (GBM) is characterized by pronounced immune escape and resistance to chemotherapy-induced apoptosis. Preliminary investigations revealed a marked overexpression of gasdermin E (GSDME) in GBM. Notably, cisplatin (CDDP) demonstrated a capacity of inducing pyroptosis by activating caspase-3 to cleave GSDME, coupled with the release of proinflammatory factors, indicating the potential as a viable approach of inducing anti-tumor immune activation. For the effective delivery of CDDP, the CDDP-polyphenol nanocomplexes were prepared, and catalase and copper ions were incorporated to fortify structural integrity, enhance glutathione (GSH) responsiveness, and ameliorate tumor hypoxia. Additionally, BV2 microglial cells were engineered to overexpress programmed death-1 (PD-1), and the membrane is employed for nanocomplex coating, effectively blocking the CDDP-induced upregulation of programmed death ligand 1 (PD-L1). Furthermore, the angiopep-2 peptide was modified to efficiently cross the blood brain barrier and specifically target GBM cells. In vitro analyses confirmed potent cytotoxicity and characteristic induction of pyroptosis. In vivo assays corroborated the enhancement of tumor targeting, culminating in an obvious suppression of tumor proliferation. A notable activation of immune cells was observed within tumors and lymph nodes, indicative of a synergistic effect of chemotherapy and immunotherapy, underscoring its potential as a safe and efficacious therapeutic strategy against GBM.

Comprehensive analysis reveals cholesterol metabolism-related signature for predicting prognosis and guiding individualized treatment of glioma

Objective

Gliomas are the most common intracranial tumors with the highest degree of malignancy. Disturbed cholesterol metabolism is one of the key features of many malignant tumors, including gliomas. This study aimed to investigate the significance of cholesterol metabolism-related genes in prognostic prediction and in guiding individualized treatment of patients with gliomas.

Methods

Transcriptional data and clinicopathological data were obtained from The Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA) databases. Intraoperative glioma samples retained in our unit and the corresponding clinicopathological information were also collected with the patients' knowledge. Firstly, cholesterol metabolism-related gene signatures (CMRGS) were identified and constructed based on difference analysis, least absolute shrinkage and selection operator (LASSO) regression analysis, and univariate/multivariate COX analysis. Then, the role of CMRGS in predicting the prognosis of gliomas and distinguishing immune landscapes was evaluated by using nomograms, survival analysis, enrichment analysis, and immune-infiltration analysis. Finally, the drug sensitivity of gliomas in different risk groups was evaluated using the oncoPredict algorithm, and potentially sensitive chemotherapeutic and molecular-targeted drugs were identified.

Results

The prognostic CMRGS contained seven genes: APOE, SCD, CXCL16, FABP5, S100A11, TNFRSF12A, and ELOVL2. Patients were divided into high- and low-risk groups based on the median cholesterol metabolic index (CMI). There were significant differences in clinicopathological characteristics and overall survival between groups. COX analysis suggested that CMRGS was an independent risk factor for glioma prognosis and had a better predictive performance than several classical indicators. In addition, GSEA, immune infiltration analysis showed that CMRGS could differentiate the immune landscapes of patients in groups. The reliability of CMRGS was validated in the CGGA cohort and our Gusu cohort. Finally, 14 drugs sensitive to high-risk patients and 16 drugs sensitive to low-risk patients were identified.

Conclusion

The CMRGS reliably predicts glioma prognosis in multiple cohorts and may be useful in guiding individualized treatment.

Enhanced Antiglioma Effect by a Vitamin D3-Inserted Lipid Hybrid Neutrophil Membrane Biomimetic Multimodal Nanoplatform

Glioblastoma, the most prevalent malignant brain tumor, is a lethal threat to human health, with aggressive and infiltrative growth characteristics that compromise the clinical treatment. Herein, we developed a vitamin D3-inserted lipid hybrid neutrophil membrane biomimetic multimodal nanoplatform (designated as NED@MnO2-DOX) through doxorubicin (DOX)-loaded manganese dioxide nanoparticles (MnO2) which were coated with a vitamin D3-inserted lipid hybrid neutrophil membrane. It was demonstrated that in addition to chemotherapy and chemo-dynamic therapy efficacy, NED@MnO2-DOX exhibited great power to activate and amplify immune responses related to the cGAS STING pathway, bolstering the secretion of type I interferon-β and proinflammatory cytokines, promoting the maturation of DC cells and infiltration of CD8+T cells into the glioma tissue, thereby reversing the immunosuppressive microenvironment of glioma from a "cold" tumor to a "hot" tumor. The biomimetic multimodal nanoplatform has potential as a multimodal strategy for glioma-targeted treatment, especially holding considerable promise for the development of innate immune therapy for glioma.

Postoperative Injection of a Triptolide-Preloaded Hydrogel Prevents the Recurrence of Glioblastoma by Dual-Pathway Activation of Ferroptosis

Glioblastoma (GBM) recurrence leads to high mortality, which remains a major concern in clinical therapy. Herein, an injectable triptolide (TP)-preloaded hydrogel (TP@DNH) accompanied by a postoperative injection strategy is developed to prevent the recurrence of GBM. With a potential inhibitor of the NRF2/SLC7A11/GPX4 axis, it is demonstrated that TP can deactivate glutathione peroxidase 4 (GPX4) from the source of glutathione (GSH) biosynthesis, thereby activating ferroptosis in GBM cells by blocking the neutralization of intracellular lipid peroxide (LPO). Based on acid-sensitive Fe3+/tannic acid (TA) metal-phenolic networks (MPNs), the TP@DNH hydrogel can induce the effective generation of reactive oxygen species (ROS) through Fe3+/TA-mediated Fenton reaction and achieve controllable release of TP in resected GBM cavity. Due to ROS generation and GPX4 deactivation, postoperative injection of TP@DNH can achieve high-level ferroptosis through dual-pathway LPO accumulation, remarkably suppressing the growth of recurrent GBM and prolonging the overall survival in orthotopic GBM relapse mouse model. This work provides an alternative paradigm for regulating ferroptosis in the postoperative treatment of GBM.

Recent advances in biomimetic strategies for the immunotherapy of glioblastoma

Immunotherapy is regarded as one of the most promising approaches for treating tumors, with a multitude of immunotherapeutic thoughts currently under consideration for the lethal glioblastoma (GBM). However, issues with immunotherapeutic agents, such as limited in vivo stability, poor blood-brain barrier (BBB) penetration, insufficient GBM targeting, and represented monotherapy, have hindered the success of immunotherapeutic interventions. Moreover, even with the aid of conventional drug delivery systems, outcomes remain suboptimal. Biomimetic strategies seek to overcome these formidable drug delivery challenges by emulating nature's intelligent structures and functions. Leveraging the variety of biological structures and functions, biomimetic drug delivery systems afford a versatile platform with enhanced biocompatibility for the co-delivery of diverse immunotherapeutic agents. Moreover, their inherent capacity to traverse the BBB and home in on GBM holds promise for augmenting the efficacy of GBM immunotherapy. Thus, this review begins by revisiting the various thoughts and agents on immunotherapy for GBM. Then, the barriers to successful GBM immunotherapy are analyzed, and the corresponding biomimetic strategies are explored from the perspective of function and structure. Finally, the clinical translation's current state and prospects of biomimetic strategy are addressed. This review aspires to provide fresh perspectives on the advancement of immunotherapy for GBM.

Open-Source Throttling of CD8+ T Cells in Brain with Low-Intensity Focused Ultrasound-Guided Sequential Delivery of CXCL10, IL-2, and aPD-L1 for Glioblastoma Immunotherapy

Improving clinical immunotherapy for glioblastoma (GBM) relies on addressing the immunosuppressive tumor microenvironment (TME). Enhancing CD8+ T cell infiltration and preventing its exhaustion holds promise for effective GBM immunotherapy. Here, a low-intensity focused ultrasound (LIFU)-guided sequential delivery strategy is developed to enhance CD8+ T cells infiltration and activity in the GBM region. The sequential delivery of CXC chemokine ligand 10 (CXCL10) to recruit CD8+ T cells and interleukin-2 (IL-2) to reduce their exhaustion is termed an "open-source throttling" strategy. Consequently, up to 3.39-fold of CD8+ T cells are observed with LIFU-guided sequential delivery of CXCL10, IL-2, and anti-programmed cell death 1 ligand 1 (aPD-L1), compared to the free aPD-L1 group. The immune checkpoint inhibitors (ICIs) therapeutic efficacy is substantially enhanced by the reversed immunosuppressive TME due to the expansion of CD8+ T cells, resulting in the elimination of tumor, prolonged survival time, and long-term immune memory establishment in orthotopic GBM mice. Overall, LIFU-guided sequential cytokine and ICIs delivery offers an "open-source throttling" strategy of CD8+ T cells, which may present a promising strategy for brain-tumor immunotherapy.

Nanomaterial-Based Repurposing of Macrophage Metabolism and Its Applications

Macrophage immunotherapy represents an emerging therapeutic approach aimed at modulating the immune response to alleviate disease symptoms. Nanomaterials (NMs) have been engineered to monitor macrophage metabolism, enabling the evaluation of disease progression and the replication of intricate physiological signal patterns. They achieve this either directly or by delivering regulatory signals, thereby mapping phenotype to effector functions through metabolic repurposing to customize macrophage fate for therapy. However, a comprehensive summary regarding NM-mediated macrophage visualization and coordinated metabolic rewiring to maintain phenotypic equilibrium is currently lacking. This review aims to address this gap by outlining recent advancements in NM-based metabolic immunotherapy. We initially explore the relationship between metabolism, polarization, and disease, before delving into recent NM innovations that visualize macrophage activity to elucidate disease onset and fine-tune its fate through metabolic remodeling for macrophage-centered immunotherapy. Finally, we discuss the prospects and challenges of NM-mediated metabolic immunotherapy, aiming to accelerate clinical translation. We anticipate that this review will serve as a valuable reference for researchers seeking to leverage novel metabolic intervention-matched immunomodulators in macrophages or other fields of immune engineering.

A Big Prospect for Hydrogel Nano-System in Glioma

Patients diagnosed with glioma typically face a limited life expectancy (around 15 months on average), a bleak prognosis, and a high likelihood of recurrence. As such, glioma is recognized as a significant form of malignancy. Presently, the treatment options for glioma include traditional approaches such as surgery, chemotherapy, and radiotherapy. Regrettably, the efficacy of these treatments has been less than optimal. Nevertheless, a promising development in glioma treatment lies in the use of hydrogel nano-systems as sophisticated delivery systems. These nano-systems have demonstrated exceptional therapeutic effects in the treatment of glioma by various responsive ways, including temperature-response, pH-response, liposome-response, ROS-response, light-response, and enzyme-response. This study seeks to provide a comprehensive summary of both the therapeutic application of hydrogel nano-systems in managing glioma and the underlying immune action mechanisms.

Microglia and macrophage metabolism: a regulator of cerebral gliomas

Reciprocal interactions between the tumor microenvironment (TME) and cancer cells play important roles in tumorigenesis and progression of glioma. Glioma-associated macrophages (GAMs), either of peripheral origin or representing brain-intrinsic microglia, are the majority population of infiltrating immune cells in glioma. GAMs, usually classified into M1 and M2 phenotypes, have remarkable plasticity and regulate tumor progression through different metabolic pathways. Recently, research efforts have increasingly focused on GAMs metabolism as potential targets for glioma therapy. This review aims to delineate the metabolic characteristics of GAMs within the TME and provide a summary of current therapeutic strategies targeting GAMs metabolism in glioma. The goal is to provide novel insights and therapeutic pathways for glioma by highlighting the significance of GAMs metabolism.