Reeducating Tumor-Associated Macrophages Using CpG@Au Nanocomposites to Modulate Immunosuppressive Microenvironment for Improved Radio-Immunotherapy

Gold nanoparticles modulate macrophage polarization to promote skeletal muscle regeneration

Skeletal muscle regeneration is a complex process that depends on the interplay between immune responses and muscle stem cell (MuSC) activity. Macrophages play a crucial role in this process, exhibiting distinct polarization states-M1 (pro-inflammatory) and M2 (anti-inflammatory)-that significantly affect tissue repair outcomes. Recent advancements in nanomedicine have positioned gold nanoparticles (Au NPs) as promising tools for modulating macrophage polarization and enhancing muscle regeneration. This review examines the role of Au NPs in influencing macrophage behavior, focusing on their physicochemical properties, biocompatibility, and mechanisms of action. We discuss how Au NPs can promote M2 polarization, facilitating tissue repair through modulation of cytokine production, interaction with cell surface receptors, and activation of intracellular signaling pathways. Additionally, we highlight the benefits of Au NPs on MuSC function, angiogenesis, and extracellular matrix remodeling. Despite the potential of Au NPs in skeletal muscle regeneration, challenges remain in optimizing nanoparticle design, developing targeted delivery systems, and understanding long-term effects. Future directions should focus on personalized medicine approaches and combination therapies to enhance therapeutic efficacy. Ultimately, this review emphasizes the transformative potential of Au NPs in regenerative medicine, offering hope for improved treatments for muscle injuries and diseases.

mtDNA/RNA boosts radiation-induced abscopal effect via M1 macrophage polarization-promoted IFN-β-dependent inflammatory response

The radiation-induced abscopal effect (RIAE) can suppress distal metastatic lesions and elicit a systemic anti-tumor response; however, the underlying mechanisms remain to be fully elucidated. Current research has shown that autophagy promotes the production of IFN-β by regulating mitochondrial DNA (mtDNA), thereby contributing to the modulation of RIAE. Nevertheless, the downstream pathways through which IFN-β influences RIAE require further investigation. In this study, we observed accumulation of an abundance of mtDNA in the cytosol of mammary tumor cells following RT, along with the presence of mitochondrial RNA (mtRNA). These molecules activated the cGAS-STING and RIG-I-MAVS signaling pathways, respectively, thereby synergistically promoting the production of IFN-β and secretion into the extracellular matrix. Subsequently, IFN-β facilitated the polarization of macrophages in distant non-irradiated tumor microenvironment towards the M1 phenotype through activating STAT1. Furthermore, our findings indicate that high linear energy transfer (LET) carbon ions are significantly more effective in inducing the production of IFN-β and promoting macrophage polarization compared to low-LET X-rays. Thus, our findings provide insights into the intricate mechanisms by which mtDNA/RNA and IFN-β mediate RIAE, suggesting that IFN-β could be a promising target for provoking RT immunogenicity in patients with breast cancer and high-LET radiation might effectively elicit RIAE.

Glioblastoma-associated macrophages in glioblastoma: from their function and mechanism to therapeutic advances

Glioblastoma multiforme (GBM) is the most aggressive primary brain tumor in adults and has high mortality rates worldwide. GBM progression, treatment, and prognosis are influenced by the tumor microenvironment (TME), which includes immune, stromal, and tumor cells. Among them, glioblastoma-associated macrophages (GAMs) act as key regulators of GBM pathobiology. GAMs exhibit remarkable plasticity, as they can exhibit both protumor and antitumor effects. However, their function is determined by polarization and the TME. In this review, we provide a comprehensive overview of the current understanding of the biology of GAMs in GBM, including their origins, phenotypic diversity, and functional roles. We discuss the intricate crosstalk between GAMs and tumor cells, as well as other immune and stromal components, and highlight the mechanisms underlying GAM-mediated tumor progression, invasion, angiogenesis, and immune system evasion. Furthermore, we explore the therapeutic implications of targeting GAMs in GBM and discuss emerging strategies aimed at reprogramming GAMs toward an antitumorigenic phenotype or selectively depleting protumorigenic subsets. The final aim is to develop innovative therapeutic approaches that disrupt GBMs. By leveraging our increased understanding of GAM biology, we lay the foundation for transformative advances in GBM treatment to improve patient prognosis.

Research progress of metal-CpG composite nanoadjuvants in tumor immunotherapy

The practical benefits and therapeutic potential of tumor vaccines in immunotherapy have drawn significant attention in the field of cancer treatment. Among the available vaccines, nanovaccines that utilize nanoparticles as carriers or adjuvants have demonstrated considerable effectiveness in combating cancer. Cytosine-phosphate-guanine oligodeoxynucleotide (CpG ODN), a common adjuvant in tumor nanovaccines, activates both humoral and cellular immunity by recognizing toll-like receptor 9 (TLR9), thereby aiding in the prevention and treatment of cancer. Metal nanoparticles hold great promise in tumor immunotherapy due to their adjustable size, surface functionalization, ability to regulate innate immunity, and capacity for controlled delivery of antigens or immunomodulators. Consequently, composite nanoadjuvants, formed by combining metal nanoparticles with CpG ODNs, can be customized to meet the specific performance requirements of different application scenarios, effectively overcoming the limitations of conventional immunotherapy approaches. This review provides a comprehensive analysis of the critical role of metal-CpG composite nanoadjuvants in advancing vaccine adjuvants for cancer therapy and prevention, highlighting their efficacy in preclinical settings.

Recent Progress in Radiosensitive Nanomaterials for Radiotherapy-Triggered Drug Release

Benefiting from the unique properties of ionizing radiation, such as high tissue penetration, spatiotemporal resolution, and clinical relevance compared with other external stimuli, radiotherapy-induced drug release strategies are showing great promise in developing effective and personalized cancer treatments. However, the requirement of high doses of X-ray irradiation to break chemical bonds for drug release limits the application of radiotherapy-induced prodrug activation in clinics. Recent advances in nanomaterials offer a promising approach for radiotherapy sensitization as well as integrating multiple modalities for improved therapy outcomes. In particular, the catalytic radiosensitization that utilizes electrons and energy generated by nanomaterials upon X-ray irradiation has demonstrated excellent potential for enhanced radiotherapy. In this Review, we summarize the design principles of X-ray-responsive chemical bonds for controlled drug release, strategies for catalytic radiosensitization, and recent progress of X-ray-responsive nanoradiosensitizers for enhanced radiotherapy by integration with chemotherapy, chemodynamic therapy, photodynamic therapy, photothermal therapy, gas therapy, and immunotherapy. Finally, we discuss the challenges of X-ray-responsive nanoradiosensitizers heading toward possible clinical translation. We expect that emerging strategies based on radiotherapy-triggered drug release will facilitate a frontier in accurate and effective cancer therapy in the near future.

Treatment-induced ripple effect: a systematic review exploring the abscopal phenomenon in Glioblastoma multiforme

PURPOSE

This systematic review aimed to collate and synthesize the available literature on the abscopal effect in Glioblastoma multiforme (GBM) neoplasms, focusing on the reported biochemical mechanisms driving the abscopal effect.

METHODS

A systematic search was conducted in PubMed, Cochrane Database of Systematic Reviews, and Epistemonikos from inception to May 1, 2023. Studies exploring the abscopal effect in GBM were included. The Clinical Relevance Assessment of Animal Preclinical research (RAA) tool was used to assess methodological quality of preclinical studies. Data on preclinical models, biochemical mechanisms, and outcomes were extracted and synthesized systrmatically.

RESULTS

Out of a total of 7 studies, five preclinical studies met the inclusion criteria. The studies utilized various in vivo mouse models, including bilateral tumor models and immunohumanized mice. Key biochemical mechanisms identified included immunogenic cell death, danger-associated molecular pattern release, macrophage activation, and enhanced T cell responses. Combinatorial approaches involving oncolytic virotherapy, nanoparticle-based treatments, radiation therapy, and immune checkpoint inhibitors showed promise in inducing abscopal effects. Significant tumor growth inhibition and improved survival were reported in treated animals. However, the RAA analysis highlighted concerns regarding research transparency and internal validity across studies.

CONCLUSIONS

This systematic review highlighted the potential of the abscopal effect in GBM, demonstrating its ability to enhance anti-tumor immune responses both locally and systemically. The synergistic effects of combinatorial approaches showed promise for improving outcomes. However, the low methodological quality of existing studies underscored the need for more rigorous preclinical research. Future studies should focus on improving research transparency, exploring the abscopal effect in other primary CNS neoplasms, and translating these findings into clinical trials to assess safety and efficacy in humans.

X-ray triggered bimetallic nanoassemblies as radiosensitizers and STING agonists for a CDT/radio-immunotherapy strategy

Radiotherapy (RT) is a cornerstone of cancer therapy, but its effectiveness is constrained by dose-limiting toxicity and inadequate systemic immune activation. To overcome these limitations, we have engineered an X-ray-responsive nanoassembly (sMnAu NAs) by cross-linking monodisperse MnAu nanoparticles (NPs) with radiation-responsive diselenide-containing linkers. MnAu alloy NPs not only provide Au NPs for radiosensitization, but also control Mn (0) release, which stimulates Fenton-like reaction for chemodynamic therapy and is transferred into Mn2+ to activate the STING pathway for immunotherapy. The responsive design not only improves tumor accumulation via EPR effect during circulation, but also achieves deep penetration of MnAu NPs following X-ray induced disassembly. The synergistic combination of chemodynamic therapy, radiotherapy and immunotherapy exhibits remarkable inhibition of tumor growth and metastasis. Overall, our sMnAu NAs represent a promising radiosensitizer for chemodynamic therapy and radiotherapy to enhance immunotherapy. STATEMENT OF SIGNIFICANCE: As a principal treatment modality in cancer management, RT is limited due to the co-irradiation of organs at risk and subsequent normal tissue toxicities. This study reported an X-ray responsive radiosensitizer prepared by cross-linking monodisperse MnAu NPs with diselenide-containing linkers. Upon X-ray irradiation, sMnAu NAs accumulate in tumors and disassemble into MnAu NPs, enabling deeper penetration. The increased surface area of MnAu NPs enhances the exposure of Mn(0), which reacts into Mn2+ and enhances ROS generation. The released Mn2+ activates the STING pathway, potentiating the X-ray-induced immune response. The synergistic integration of CDT, RT, and immunotherapy results in a potent suppression of tumor growth and metastasis. Collectively, this X-ray activatable CDT/radio-immunotherapy strategy holds great potential for effective cancer treatment.

Polyinosinic/Polycytidylic Lipid Nanoparticles Enhance Immune Cell Infiltration and Improve Survival in the Glioblastoma Mouse Model

Glioblastoma (GBM) immunotherapy is particularly challenging due to the pro-tumorigenic microenvironment, marked by low levels and inactive immune cells. Toll-like receptor (TLR) agonists have emerged as potent immune adjuvants but failed to show improved outcomes in clinical trials when administered as a monotherapy. We hypothesize that a combined nanoparticulate formulation of TLR agonist and immunogenic cell death-inducing drug (doxorubicin) will synergize to induce improved GBM immunotherapy. Lipid nanoparticle (LNP) formulations of the TLR agonists CpG and polyinosinic/polycytidylic (pIpC), with and without Dox, were first prepared, achieving an encapsulation efficiency >75% and a size <140 nm. In vitro studies identified that LNP pIpC was superior to CpG at activating bone marrow-derived immune cell populations (dendritic cells and macrophages) with minimal toxicity. It was also observed that the pIpC formulation can skew macrophage polarization toward the antitumorigenic M1 phenotype and increase macrophage phagocytosis of cancer cells. Upon intratumoral administration, pIpC Dox LNPs led to significant immune cell infiltration and activation. In survival models, the inclusion of Dox into pIpC LNP improved mice survival compared to control. However, addition of Dox did not show significant improvement in mice's survival compared to singly formulated pIpC LNP. This study has illustrated the potential of pIpC LNP formulations in prospective GBM immunotherapeutic regimes. Future studies will focus on optimizing dosage regimen and/or combination with other modalities, including the standard of care (temozolomide), immune checkpoint blockade, or cancer vaccines.

Nanomaterial-assisted delivery of CpG oligodeoxynucleotides for boosting cancer immunotherapy

Cancer immunotherapy aims to improve immunity to not only eliminate the primary tumor but also inhibit metastasis and recurrence. It is considered an extremely promising therapeutic approach that breaks free from the traditional paradigm of oncological treatment. As the medical community learns more about the immune system's mechanisms that "turn off the brake" and "step on the throttle", there is increasingly successful research on immunomodulators. However, there are still more restrictions than countermeasures with immunotherapy related to immunomodulators, such as low responsiveness and immune-related adverse events that cause multiple adverse reactions. Therefore, medical experts and materials scientists attempted to the efficacy of immunomodulatory treatments through various methods, especially nanomaterial-assisted strategies. CpG oligodeoxynucleotides (CpG) not only act as an adjuvant to promote immune responses, but also induce autophagy. In this review, the enhancement of immunotherapy using nanomaterial-based CpG formulations is systematically elaborated, with a focus on the delivery, protection, synergistic promotion of CpG efficacy by nanomaterials, and selection of the timing of treatment. In addition, we also discuss and prospect the existing problems and future directions of research on nanomaterials in auxiliary CpG therapy.

Nanoradiosensitizers in glioblastoma treatment: recent advances and future perspectives

Glioblastoma (GBM), a highly invasive type of brain tumor located within the central nervous system, manifests a median survival time of merely 14.6 months. Radiotherapy kills tumor cells through focused high-energy radiation and has become a crucial treatment strategy for GBM, especially in cases where surgical resection is not viable. However, the presence of radioresistant tumor cells limits its clinical effectiveness. Radioresistance is a key factor of treatment failure, prompting the development of various therapeutic strategies to overcome this challenge. With the rapid development of nanomedicine, nanoradiosensitizers provide a novel approach to enhancing the effectiveness of radiotherapy. In this review, we discuss the reasons behind GBM radio-resistance and the mechanisms of radiotherapy sensitization. Then we summarize the primary types of nanoradiosensitizers and recent progress in their application for the radiosensitization of GBM. Finally, we elucidate the factors influencing their practical implementation, along with the challenges and promising prospects associated with multifunctional nanoradiosensitizers.

S-Sulfenylation Driven Antigen Capture Boosted by Radiation for Enhanced Cancer Immunotherapy

Radiotherapy (RT)-induced in situ vaccination greatly promotes the development of personalized cancer vaccines owing to the massive release of antigens initiated by tumor-localized RT eliciting the tumor-specific immune response. However, its broad application in cancer treatment is seriously impeded by poor antigen cross-presentation, low response rate, and short duration of efficacy. Herein, the tumor-antigen-capturing nanosystem dAuNPs@CpG consisting of gold nanoparticles, 3,5-cyclohexanedione (CHD), and immunoadjuvant CpG were fabricated to enhance RT-induced vaccination. Taking advantage of the specific covalent binding between CHD and sulfenic acids of antigen proteins, we show that this nanoplatform has an unexpected potential to capture the sulfenylated tumor-derived protein antigens (TDPAs) induced by RT to in situ generate a vaccination effect, achieving significant growth suppression of both primary and distant tumors in combination with PD-1 blockade. We thus believe that our work presents a powerful and effective means to improve the synergistic tumor radioimmunotherapy.

An erythrocyte membrane-camouflaged fluorescent covalent organic framework for starving/nitric oxide/immunotherapy of triple-negative breast cancer

It is a great challenge to effectively treat triple-negative breast cancer (TNBC) due to lack of therapeutic targets and drug resistance of systemic chemotherapy. Rational design of nanomedicine with good hemocompatibility is urgently desirable for combination therapy of TNBC. Herein, an erythrocyte membrane-camouflaged fluorescent covalent organic framework (COF) loaded with an NO donor (hydroxyurea, Hu), glucose oxidase (GOx) and cytosine-phosphate-guanine oligonucleotides (CPG) (COF@HGC) was developed for imaging-guided starving/nitric oxide (NO)/immunization synergistic treatment of TNBC. The substances of HGC are easily co-loaded onto the COF due to the ordered pore structure and large surface area. And a folic acid-modified erythrocyte membrane (FEM) is coated on the surface of COF@HGC to improve targeted therapy and haemocompatibility. When COF@HGC@FEM is internalized into tumor cells, hemoglobin (Hb) on FEM and GOx loaded on the COF can trigger cascade reactions to kill tumor cells due to the simultaneous production of NO and exhaustion of glucose. Meanwhile, the COF with excellent fluorescence properties can be used as a self-reporter for bioimaging. Furthermore, the CPG can reprogram tumor-associated macrophages from tumor-supportive phenotype to anti-tumor phenotype and enhance immunotherapy. Through the "three-in-one" strategy, the biomimetic nanoplatform can effectively inhibit tumor growth and reprogram the tumor immunosuppression microenvironment in the TNBC mouse model.

Targeting tumor-associated macrophage: an adjuvant strategy for lung cancer therapy

The emergence of immunotherapy has revolutionized the treatment landscape for various types of cancer. Nevertheless, lung cancer remains one of the leading causes of cancer-related mortality worldwide due to the development of resistance in most patients. As one of the most abundant groups of immune cells in the tumor microenvironment (TME), tumor-associated macrophages (TAMs) play crucial and complex roles in the development of lung cancer, including the regulation of immunosuppressive TME remodeling, metabolic reprogramming, neoangiogenesis, metastasis, and promotion of tumoral neurogenesis. Hence, relevant strategies for lung cancer therapy, such as inhibition of macrophage recruitment, TAM reprograming, depletion of TAMs, and engineering of TAMs for drug delivery, have been developed. Based on the satisfactory treatment effect of TAM-targeted therapy, recent studies also investigated its synergistic effect with current therapies for lung cancer, including immunotherapy, radiotherapy, chemotherapy, anti-epidermal growth factor receptor (anti-EGFR) treatment, or photodynamic therapy. Thus, in this article, we summarized the key mechanisms of TAMs contributing to lung cancer progression and elaborated on the novel therapeutic strategies against TAMs. We also discussed the therapeutic potential of TAM targeting as adjuvant therapy in the current treatment of lung cancer, particularly highlighting the TAM-centered strategies for improving the efficacy of anti-programmed cell death-1/programmed cell death-ligand 1 (anti-PD-1/PD-L1) treatment.

Catalytic MnWO4 Nanorods for Chemodynamic Therapy Synergized Radiotherapy of Triple Negative Breast Cancer

Nanomedicine‐based synergy of chemodynamic therapy (CDT) and radiotherapy (RT) modulated by tumor microenvironment enables rapid tumor ablation, which holds great hope for the refractory and recurrent cancers, such as triple negative breast cancer (TNBC). The clinical translation of hafnium oxide (HfO2), commercially named as NBTXR3, has aroused new research focus on single‐component inorganic nanomedicines as clinical candidates. Herein, the single‐component MnWO4 is first reported as a new kind of Fenton‐like agent yet radiosensitizer for TNBC treatment undergoing the synergistic CDT/RT mechanism. MnWO4 nanorods are synthesized via a simple one‐pot hydrothermal method and then undergo a layer‐by‐layer PEGylation to obtain bioavailable MnWO4‐PEG (MWP). MWP‐based Fenton‐like reaction efficacy depends on reaction time, temperatures, pH values, and MWP concentrations. Mn‐triggered chemodynamic effect delays RT‐induced DNA damage repair and sorts cell cycles distribution toward radiosensitive phases, while W‐mediated radiosensitization improves the tumoral H2O2 overexpression to enhance CDT, remarkably amplifying of the intracellular oxidative stress to boost 4T1 cell apoptosis. In vitro and in vivo evaluations further demonstrate the effectiveness and biosafety of MWP‐based synergistic therapy. Considering the potential magnetic resonance and computed tomography imaging capabilities, MWP can be expected as an intelligent cancer theranostics for imaging‐guided cancer therapy in clinic in the future.

Radiotherapy combined with nano-biomaterials for cancer radio-immunotherapy

Radiotherapy (RT) plays an important role in tumor therapy due to its noninvasiveness and wide adaptation. In recent years, radiation therapy has been discovered to induce an anti-tumor immune response, which arouses widespread concern among scientists and clinicians. In this review, we highlight recent advances in the applications of nano-biomaterials for radiotherapy-activated immunotherapy. We first discuss the combination of different radiosensitizing nano-biomaterials and immune checkpoint inhibitors to enhance tumor immune response and improve radiotherapy efficacy. Subsequently, various nano-biomaterials-enabled tumor oxygenation strategies are introduced to alleviate the hypoxic tumor environment and amplify the immunomodulatory effect. With the aid of nano-vaccines and adjuvants, radiotherapy refreshes the host's immune system. Additionally, ionizing radiation responsive nano-biomaterials raise innate immunity-mediated anti-tumor immunity. At last, we summarize the rapid development of immune modulatable nano-biomaterials and discuss the key challenge in the development of nano-biomaterials for tumor radio-immunotherapy. Understanding the nano-biomaterials-assisted radio-immunotherapy will maximize the benefits of clinical radiotherapy and immunotherapy and facilitate the development of new combinational therapy modality.

The Importance of M1-and M2-Polarized Macrophages in Glioma and as Potential Treatment Targets

Glioma is the most common and malignant tumor of the central nervous system. Glioblastoma (GBM) is the most aggressive glioma, with a poor prognosis and no effective treatment because of its high invasiveness, metabolic rate, and heterogeneity. The tumor microenvironment (TME) contains many tumor-associated macrophages (TAMs), which play a critical role in tumor proliferation, invasion, metastasis, and angiogenesis and indirectly promote an immunosuppressive microenvironment. TAM is divided into tumor-suppressive M1-like (classic activation of macrophages) and tumor-supportive M2-like (alternatively activated macrophages) polarized cells. TAMs exhibit an M1-like phenotype in the initial stages of tumor progression, and along with the promotion of lysing tumors and the functions of T cells and NK cells, tumor growth is suppressed, and they rapidly transform into M2-like polarized macrophages, which promote tumor progression. In this review, we discuss the mechanism by which M1- and M2-polarized macrophages promote or inhibit the growth of glioblastoma and indicate the future directions for treatment.

Tumor-associated macrophage-related strategies for glioma immunotherapy

High-grade glioma is one of the deadliest primary tumors of the central nervous system. Despite the many novel immunotherapies currently in development, it has been difficult to achieve breakthrough results in clinical studies. The reason may be due to the suppressive tumor microenvironment of gliomas that limits the function of specific immune cells (e.g., T cells) which are currently the primary targets of immunotherapy. However, tumor-associated macrophage, which are enriched in tumors, plays an important role in the development of GBM and is becoming a research hotspot for immunotherapy. This review focuses on current research advances in the use of macrophages as therapeutic targets or therapeutic tools for gliomas, and provides some potential research directions.

A MOF-Based Potent Ferroptosis Inducer for Enhanced Radiotherapy of Triple Negative Breast Cancer

Radiotherapy (RT) is one of the important clinical treatments for local control of triple-negative breast cancer (TNBC), but radioresistance still exists. Ferroptosis has been recognized as a natural barrier for cancer progression and represents a significant role of RT-mediated anticancer effects, while the simultaneous activation of ferroptosis defensive system during RT limits the synergistic effect between RT and ferroptosis. Herein, we engineered a tumor microenvironment (TME) degradable nanohybrid with a dual radiosensitization manner to combine ferroptosis induction and high-Z effect based on metal-organic frameworks for ferroptosis-augmented RT of TNBC. The encapsulated l-buthionine-sulfoximine (BSO) could inhibit glutathione (GSH) biosynthesis for glutathione peroxidase 4 (GPX4) inactivation to break down the ferroptosis defensive system, and the delivered ferrous ions could act as a powerful ferroptosis executor via triggering the Fenton reaction; the combination of them induces potent ferroptosis, which could synergize with the surface decorated Gold (Au) NPs-mediated radiosensitization to improve RT efficacy. In vivo antitumor results revealed that the nanohybrid could significantly improve the therapeutic efficacy and antimetastasis efficiency based on the combinational mechanism between ferroptosis and RT. This work thus demonstrated that combining RT with efficient ferroptosis induction through nanotechnology was a feasible and promising strategy for TNBC treatment.

Gold Nanoparticles: Construction for Drug Delivery and Application in Cancer Immunotherapy

Cancer immunotherapy is an innovative treatment strategy to enhance the ability of the immune system to recognize and eliminate cancer cells. However, dose limitations, low response rates, and adverse immune events pose significant challenges. To address these limitations, gold nanoparticles (AuNPs) have been explored as immunotherapeutic drug carriers owing to their stability, surface versatility, and excellent optical properties. This review provides an overview of the advanced synthesis routes for AuNPs and their utilization as drug carriers to improve precision therapies. The review also emphasises various aspects of AuNP-based immunotherapy, including drug loading, targeting strategies, and drug release mechanisms. The application of AuNPs combined with cancer immunotherapy and their therapeutic efficacy are briefly discussed. Overall, we aimed to provide a recent understanding of the advances, challenges, and prospects of AuNPs for anticancer applications.

Radiation-induced tumor immune microenvironments and potential targets for combination therapy

As one of the four major means of cancer treatment including surgery, radiotherapy (RT), chemotherapy, immunotherapy, RT can be applied to various cancers as both a radical cancer treatment and an adjuvant treatment before or after surgery. Although RT is an important modality for cancer treatment, the consequential changes caused by RT in the tumor microenvironment (TME) have not yet been fully elucidated. RT-induced damage to cancer cells leads to different outcomes, such as survival, senescence, or death. During RT, alterations in signaling pathways result in changes in the local immune microenvironment. However, some immune cells are immunosuppressive or transform into immunosuppressive phenotypes under specific conditions, leading to the development of radioresistance. Patients who are radioresistant respond poorly to RT and may experience cancer progression. Given that the emergence of radioresistance is inevitable, new radiosensitization treatments are urgently needed. In this review, we discuss the changes in irradiated cancer cells and immune cells in the TME under different RT regimens and describe existing and potential molecules that could be targeted to improve the therapeutic effects of RT. Overall, this review highlights the possibilities of synergistic therapy by building on existing research.

Intelligent delivery system targeting PD-1/PD-L1 pathway for cancer immunotherapy

The drugs targeting the PD-1/PD-L1 pathway have gained abundant clinical applications for cancer immunotherapy. However, only a part of patients benefit from such immunotherapy. Thus, brilliant novel tactic to increase the response rate of patients is on the agenda. Nanocarriers, particularly the rationally designed intelligent delivery systems with controllable therapeutic agent release ability and improved tumor targeting capacity, are firmly recommended. In light of this, state-of-the-art nanocarriers that are responsive to tumor-specific microenvironments (internal stimuli, including tumor acidic microenvironment, high level of GSH and ROS, specifically upregulated enzymes) or external stimuli (e.g., light, ultrasound, radiation) and release the target immunomodulators at tumor sites feature the advantages of increased anti-tumor potency but decreased off-target toxicity. Given the fantastic past achievements and the rapid developments in this field, the future is promising. In this review, intelligent delivery platforms targeting the PD-1/PD-L1 axis are attentively appraised. Specifically, mechanisms of the action of these stimuli-responsive drug release platforms are summarized to raise some guidelines for prior PD-1/PD-L1-based nanocarrier designs. Finally, the conclusion and outlook in intelligent delivery system targeting PD-1/PD-L1 pathway for cancer immunotherapy are outlined.

X-Ray Activatable Au/Ag Nanorods for Tumor Radioimmunotherapy Sensitization and Monitoring of the Therapeutic Response Using NIR-II Photoacoustic Imaging

Radioimmunotherapy (RIT) is an advanced physical therapy used to kill primary cancer cells and inhibit the growth of distant metastatic cancer cells. However, challenges remain because RIT generally has low efficacy and serious side effects, and its effects are difficult to monitor in vivo. This work reports that Au/Ag nanorods (NRs) enhance the effectiveness of RIT against cancer while allowing the therapeutic response to be monitored using activatable photoacoustic (PA) imaging in the second near-infrared region (NIR-II, 1000-1700 nm). The Au/Ag NRs can be etched using high-energy X-ray to release silver ions (Ag+ ), which promotes dendritic cell (DC) maturation, enhances T-cell activation and infiltration, and effectively inhibits primary and distant metastatic tumor growth. The survival time of metastatic tumor-bearing mice treated with Au/Ag NR-enhanced RIT is 39 days compared with 23 days in the PBS control group. Furthermore, the surface plasmon absorption intensity at 1040 nm increases fourfold after Ag+ are released from the Au/Ag NRs, allowing X-ray activatable NIR-II PA imaging to monitor the RIT response with a high signal-to-background ratio of 24.4. Au/Ag NR-based RIT has minimal side effects and shows great promise for precise cancer RIT.

Novel strategies for tumor radiosensitization mediated by multifunctional gold-based nanomaterials

Radiotherapy (RT) is one of the most effective and commonly used cancer treatments for malignant tumors. However, the existing radiosensitizers have a lot of side effects and poor efficacy, which limits the curative effect and further application of radiotherapy. In recent years, emerging nanomaterials have shown unique advantages in enhancing radiosensitization. In particular, gold-based nanomaterials, with high X-ray attenuation capacity, good biocompatibility, and promising chemical, electronic and optical properties, have become a new type of radiotherapy sensitizer. In addition, gold-based nanomaterials can be used as a carrier to load a variety of drugs and immunosuppressants; in particular, its photothermal therapy, photodynamic therapy and multi-mode imaging functions aid in providing excellent therapeutic effect in coordination with RT. Recently, many novel strategies of radiosensitization mediated by multifunctional gold-based nanomaterials have been reported, which provides a new idea for improving the efficacy and reducing the side effects of RT. In this review, we systematically summarize the recent progress of various new gold-based nanomaterials that mediate radiosensitization and describe the mechanism. We further discuss the challenges and prospects in the field. It is hoped that this review will help researchers understand the latest progress of gold-based nanomaterials for radiosensitization, and encourage people to optimize the existing methods or explore novel approaches for radiotherapy.

A Catalytic Immune Activator Based on Magnetic Nanoparticles to Reprogram the Immunoecology of Breast Cancer from "Cold" to "Hot" State

Triple-negative breast cancer (TNBC) as "cold" tumor is characterized by severe immunosuppression of the tumor microenvironment (TME). To effectively activate the immune response of TNBC, a new kind of therapy strategy called cancer catalytic immunotherapy is proposed based on magnetic nanoparticles (NPs) as immune activators. Utilizing the weak acidity and excessive hydrogen peroxide of TME, these magnetic NPs can release ferrous ions to promote Fenton reaction, leading to abundant ·OH and reactive oxygen species (ROS) for ultimately killing cancer cells. Mechanistically, these magnetic NPs activate the ROS-related signaling pathway to generate more ROS. Meanwhile, these magnetic NPs with unique immunological properties can promote the maturation of dendritic cells and the polarization of macrophages from M2 to M1, resulting in the infiltration of more T cells to reprogram the immunoecology of TNBC from "cold" to "hot" state. Besides directly affecting immune cells, these magnetic NPs can also affect the secretion of some immune-related cytokines by cancer cells, to further indirectly activate the immune response. In conclusion, these catalytic immune activators are designed to achieve the synergistic treatment of chemodynamic therapy-enhanced immunotherapy guided by computed tomography (CT)/near-infrared region-II (NIR-II) dual-mode imaging, providing a new strategy for TNBC treatment.

Targeting tumor-associated macrophages for the immunotherapy of glioblastoma: Navigating the clinical and translational landscape

Tumor-associated macrophages (TAMs) can directly clear tumor cells and enhance the phagocytic ability of immune cells. An abundance of TAMs at the site of the glioblastoma tumor indicates that TAM-targeting immunotherapy could represent a potential form of treatment for this aggressive cancer. Herein, we discuss: i) the dynamic role of TAMs in glioblastoma; ii) describe the formation of the immunosuppressive tumor microenvironment; iii) summarize the latest clinical trial data that reveal how TAM function can be regulated in favor tumor eradication; and lastly, iv) evaluate the implications of existing and novel translational approaches for treating glioblastoma in clinical practice.

Tumor-Tropic Adipose-Derived Mesenchymal Stromal Cell Mediated Bi2 Se3 Nano-Radiosensitizers Delivery for Targeted Radiotherapy of Non-Small Cell Lung Cancer

With the successful marriage between nanotechnology and oncology, various high-Z element containing nanoparticles (NPs) are approved as radiosensitizers to overcome radiation resistance for enhanced radiotherapy (RT). Unfortunately, NPs themselves lack specificity to tumors. Due to the inherent tropism nature of malignant cells, mesenchymal stem cells (MSCs) emerge as cell-mediated delivery vehicles for functional NPs to improve their therapeutic index. Herein, radiosensitive bismuth selenide (Bi₂ Se₃ ) NPs-laden adipose-derived mesenchymal stromal cells (AD-MSCs/Bi₂ Se₃ ) are engineered for targeted RT of non-small cell lung cancer (NSCLC). The results reveal that the optimized intracellular loading strategy hardly affects cell viability, specific surface markers, or migration capability of AD-MSCs, and Bi₂ Se₃  NPs can be efficiently transported from AD-MSCs to tumor cells. In vivo biodistribution test shows that the Bi₂ Se₃ NPs accumulation in tumor is increased 20 times via AD-MSCs-mediated delivery. Therefore, AD-MSCs/Bi₂ Se₃ administration synchronized with X-ray irradiation controls the tumor progress well in orthotopic A549 tumor bearing mice. Considering that MSCs migrate better to irradiated tumor cells in comparison to nonirradiated ones and MSCs preferentially accumulate within lung tissues after systemic administration into accounts, the tumor-tropic MSCs/NPs system is feasible and promising for targeted RT treatment of NSCLC.

Glycoconjugate Nanoparticle-Based Systems in Cancer Immunotherapy: Novel Designs and Recent Updates

For many years, cell-surface glycans (in particular, Tumor-Associated Carbohydrate Antigens, TACAs) have been the target of both passive and active anticancer immunotherapeutic design. Recent advances in immunotherapy as a treatment for a variety of malignancies has revolutionized anti-tumor treatment regimens. Checkpoint inhibitors, Chimeric Antigen Receptor T-cells, Oncolytic virus therapy, monoclonal antibodies and vaccines have been developed and many approvals have led to remarkable outcomes in a subset of patients. However, many of these therapies are very selective for specific patient populations and hence the search for improved therapeutics and refinement of techniques for delivery are ongoing and fervent research areas. Most of these agents are directed at protein/peptide epitopes, but glycans-based targets are gaining in popularity, and a handful of approved immunotherapies owe their activity to oligosaccharide targets. In addition, nanotechnology and nanoparticle-derived systems can help improve the delivery of these agents to specific organs and cell types based on tumor-selective approaches. This review will first outline some of the historical beginnings of this research area and subsequently concentrate on the last 5 years of work. Based on the progress in therapeutic design, predictions can be made as to what the future holds for increasing the percentage of positive patient outcomes for optimized systems.

Development of nanotechnology-mediated precision radiotherapy for anti-metastasis and radioprotection

Radiotherapy (RT), including external beam RT and internal radiation therapy, uses high-energy ionizing radiation to kill tumor cells.