Nanomaterials for Combinational Radio–Immuno Oncotherapy

Nanotechnology-enhanced radiotherapy and the abscopal effect: Current status and challenges of nanomaterial-based radio-immunotherapy

Rare but consistent reports of abscopal remission in patients challenge the notion that radiotherapy (RT) is a local treatment; radiation-induced cancer cell death can trigger activation and recruitment of dendritic cells to the primary tumor site, which subsequently initiates systemic immune responses against metastatic lesions. Although this abscopal effect was initially considered an anomaly, combining RT with immune checkpoint inhibitor therapies has been shown to greatly improve the incidence of abscopal responses via modulation of the immunosuppressive tumor microenvironment. Preclinical studies have demonstrated that nanomaterials can further improve the reliability and potency of the abscopal effect for various different types of cancer by (1) altering the cell death process to be more immunogenic, (2) facilitating the capture and transfer of tumor antigens from the site of cancer cell death to antigen-presenting cells, and (3) co-delivering immune checkpoint inhibitors along with radio-enhancing agents. Several unanswered questions remain concerning the exact mechanisms of action for nanomaterial-enhanced RT and for its combination with immune checkpoint inhibition and other immunostimulatory treatments in clinically relevant settings. The purpose of this article is to summarize key recent developments in this field and also highlight knowledge gaps that exist in this field. An improved mechanistic understanding will be critical for clinical translation of nanomaterials for advanced radio-immunotherapy. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Synergistically Enhancing Immunotherapy Efficacy in Glioblastoma with Gold-Core Silica-Shell Nanoparticles and Radiation

Purpose

Glioblastoma is a highly aggressive brain tumor with universally poor outcomes. Recent progress in immune checkpoint inhibitors has led to increased interest in their application in glioblastoma. Nonetheless, the unique immune milieu in the brain has posed remarkable challenges to the efficacy of immunotherapy. We aimed to leverage the radiation-induced immunogenic cell death to overcome the immunosuppressive network in glioblastoma.

Methods

We developed a novel approach using the gold-core silica-shell nanoparticles (Au@SiO2 NPs) in combination with low-dose radiation to enhance the therapeutic efficacy of the immune checkpoint inhibitor (atezolizumab) in brain tumors. The biocompatibility, immune cell recruitment, and antitumor ability of the combinatorial strategy were determined using in vitro assays and in vivo models.

Results

Our approach successfully induced the migration of macrophages towards brain tumors and promoted cancer cell apoptosis. Subcutaneous tumor models demonstrated favorable safety profiles and significantly enhanced anticancer effects. In orthotopic brain tumor models, the multimodal therapy yielded substantial prognostic benefits over any individual modalities, achieving an impressive 40% survival rate.

Conclusion

In summary, the combination of Au@SiO2 NPs and low-dose radiation holds the potential to improve the clinical efficacy of immune checkpoint inhibitors. The synergetic strategy modulates tumor microenvironments and enhances systemic antitumor immunity, paving a novel way for glioblastoma treatment.

MXene-Based Functional Platforms for Tumor Therapy

Recently, 2D transition metal carbide, nitride, and carbonitrides (MXenes) materials stand out in the field of tumor therapy, particularly in the construction of functional platforms for optimal antitumor therapy due to their high specific surface area, tunable performance, strong absorption of near-infrared light as well as preferable surface plasmon resonance effect. In this review, the progress of MXene-mediated antitumor therapy is summarized after appropriate modifications or integration procedures. The enhanced antitumor treatments directly performed by MXenes, the significant improving effect of MXenes on different antitumor therapies, as well as the MXene-mediated imaging-guided antitumor strategies are discussed in detail. Moreover, the existing challenges and future development directions of MXenes in tumor therapy are presented.

Regulating electron transportation by tungsten oxide nanocapacitors for enhanced radiation therapy

In the process of radiation therapy (RT), the cytotoxic effects of excited electrons generated from water radiolysis tend to be underestimated due to multiple biochemical factors, particularly the recombination between electrons and hydroxyl radicals (·OH). To take better advantage of radiolytic electrons, we constructed WO₃ nanocapacitors that reversibly charge and discharge electrons to regulate electron transportation and utilization. During radiolysis, WO₃ nanocapacitors could contain the generated electrons that block electron-·OH recombination and contribute to the yield of ·OH at a high level. These contained electrons could be discharged from WO₃ nanocapacitors after radiolysis, resulting in the consumption of cytosolic NAD⁺ and impairment of NAD⁺-dependent DNA repair. Overall, this strategy of nanocapacitor-based radiosensitization improves the radiotherapeutic effects by increasing the utilization of radiolytic electrons and ·OH, warranting further validation in multiple tumour models and preclinical experiments.

Nanoparticle-Mediated Radiotherapy Remodels the Tumor Microenvironment to Enhance Antitumor Efficacy

Radiotherapy (RT) uses ionizing radiation to eradicate localized tumors and, in rare cases, control tumors outside of the irradiated fields via stimulating an antitumor immune response (abscopal effect). However, the therapeutic effect of RT is often limited by inherent physiological barriers of the tumor microenvironment (TME), such as hypoxia, abnormal vasculature, dense extracellular matrix (ECM), and an immunosuppressive TME. Thus, it is critical to develop new RT strategies that can remodel the TME to overcome radio-resistance and immune suppression. In the past decade, high-Z-element nanoparticles have been developed to increase radiotherapeutic indices of localized tumors by reducing X-ray doses and side effects to normal tissues and enhance abscopal effects by activating the TME to elicit systemic antitumor immunity. In this review, the principles of RT and radiosensitization, the mechanisms of radio-resistance and immune suppression, and the use of various nanoparticles to sensitize RT and remodel TMEs for enhanced antitumor efficacy are discussed. The challenges in clinical translation of multifunctional TME-remodeling nanoradiosensitizers are also highlighted.

Aerosolized immunotherapeutic nanoparticle inhalation potentiates PD-L1 blockade for locally advanced lung cancer

Despite therapeutic advancements, the prognosis of locally advanced non-small cell lung cancer (LANSCLC), which has invaded multiple lobes or the other lung and intrapulmonary lymph nodes, remains poor. The emergence of immunotherapy with immune checkpoint blockade (ICB) is transforming cancer treatment. However, only a fraction of lung cancer patients benefit from ICB. Significant clinical evidence suggests that the proinflammatory tumor microenvironment (TME) and programmed death-ligand 1 (PD-L1) expression correlate positively with response to the PD-1/PD-L1 blockade. We report here a liposomal nanoparticle loaded with cyclic dinucleotide and aerosolized (AeroNP-CDN) for inhalation delivery to deep-seated lung tumors and target CDN to activate stimulators of interferon (IFN) genes in macrophages and dendritic cells (DCs). Using a mouse model that recapitulates the clinical LANSCLC, we show that AeroNP-CDN efficiently mitigates the immunosuppressive TME by reprogramming tumor-associated macrophage from the M2 to M1 phenotype, activating DCs for effective tumor antigen presentation and increasing tumor-infiltrating CD8⁺ T cells for adaptive anticancer immunity. Intriguingly, activation of interferons by AeroNP-CDN also led to increased PD-L1 expression in lung tumors, which, however, set a stage for response to anti-PD-L1 treatment. Indeed, anti-PD-L1 antibody-mediated blockade of IFNs-induced immune inhibitory PD-1/PD-L1 signaling further prolonged the survival of the LANSCLC-bearing mice. Importantly, AeroNP-CDN alone or combination immunotherapy was safe without local or systemic immunotoxicity. In conclusion, this study demonstrates a potential nano-immunotherapy strategy for LANSCLC, and mechanistic insights into the evolution of adaptive immune resistance provide a rational combination immunotherapy to overcome it.

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.

Nanoparticle-Mediated STING Activation for Cancer Immunotherapy

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

The application of nanoparticles in immunotherapy for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) remains one of the leading causes of cancer-related deaths worldwide, however, current clinical diagnostic and treatment approaches remain relatively limited, creating an urgent need for the development of effective technologies. Immunotherapy has emerged as a powerful treatment strategy for advanced cancer. The number of clinically approved drugs for HCC immunotherapy has been increasing. However, it remains challenging to improve their transport and therapeutic efficiency, control their targeting and release, and mitigate their adverse effects. Nanotechnology has recently gained attention for improving the effectiveness of precision therapy for HCC. We summarize the key features of HCC associated with nanoparticle (NPs) targeting, release, and uptake, the roles and limitations of several major immunotherapies in HCC, the use of NPs in immunotherapy, the properties of NPs that influence their design and application, and current clinical trials of NPs in HCC, with the aim of informing the design of delivery platforms that have the potential to improve the safety and efficacy of HCC immunotherapy，and thus, ultimately improve the prognosis of HCC patients.

Self-Cooperative Prodrug Nanovesicles Migrate Immune Evasion to Potentiate Chemoradiotherapy in Head and Neck Cancer

Chemoradiotherapy is the standard of care for the clinical treatment of locally advanced head and neck cancers. However, the combination of ion radiation with free chemotherapeutics yields unsatisfactory therapeutic output and severe side effects due to the nonspecific biodistribution of the anticancer drugs. Herein, a self-cooperative prodrug nanovesicle is reported for highly tumor-specific chemoradiotherapy. The nanovesicles integrating a prodrug of oxaliplatin (OXA) can passively accumulate at the tumor site and penetrate deep into the tumor mass via matrix metalloproteinase 2-mediated cleavage of the polyethylene glycol corona. The OXA prodrug can be restored inside the tumor cells with endogenous glutathione to trigger immunogenic cell death (ICD) of the tumor cells and sensitize the tumor to ion radiation. The nanovesicles can be further loaded with the JAK inhibitor ruxolitinib to abolish chemoradiotherapy-induced programmed death ligand 1 (PD-L1) upregulation on the surface of the tumor cells, thereby prompting chemoradiotherapy-induced immunotherapy by blocking the interferon gamma-Janus kinase-signal transducer and activator of transcription axis. The prodrug nanoplatform reported herein might present a novel strategy to cooperatively enhance chemoradiotherapy of head and cancer and overcome PD-L1-dependent immune evasion.

Lactic acid modified rare earth-based nanomaterials for enhanced radiation therapy by disturbing the glycolysis

Deficient deposition of X-rays and strong capacity of repairing damage DNA of cancer cells limit the effect of radiation therapy (RT). Herein, we synthesize CsLu₂F₇ nanoparticles with lactic acid (LA) ligands (CsLu₂F₇-LA) to overcome these limitations. The high-Z atoms of Lu and Cs can deposit more X-rays for generating enhanced hydroxyl radicals (·OH). Meanwhile, the LA ligand will guide CsLu₂F₇-LA to target monocarboxylic acid transporter (MCT) and impede the transportation of free LA, leading to decreased glycolysis and DNA damage repair. Consequently, the curative effect of RT will be enhanced and the strategy of LA accumulation induced radiosensitization is proved by in vivo and in vitro experiments, which will bring prospects for enhanced RT with nanomedicine.

Protein Binding Nanoparticles as an Integrated Platform for Cancer Diagnosis and Treatment

Smart nanomaterials constitute a new approach toward safer and more effective combined anti-cancer immunotherapy. In this study, polydopamine-multiprotein conjugates (DmPCs) that can be used for targeted delivery of multiple proteins to cells, realize imaging and combine the advantages of multiple treatment methods (photothermal therapy, chemodynamic therapy, and immunotherapy) can be synthesized and characterized. Proteins, as biological agents, are frequently used in this context, given their low toxicity in vivo. To overcome protein instability and short half-life in vivo, the use of several proteins in combination with selected nanomaterials to treat patients with melanoma is proposed. In addition to the synthesis and characterization of protein-bound nanoparticles, it is further demonstrated that several proteins can be efficiently delivered to tumor sites. DmPCs have a wide range of potential adaptability, which provides new opportunities for proteins in the field of treatment and imaging.

Chemical Modulation of Glucose Metabolism with a Fluorinated CaCO3 Nanoregulator Can Potentiate Radiotherapy by Programming Antitumor Immunity

Tumor hypoxia and acidity are well-known features in solid tumors that cause immunosuppression and therapeutic resistance. Herein, we rationally synthesized a multifunctional fluorinated calcium carbonate (fCaCO₃) nanoregulator by coating CaCO₃ nanoparticles with dopamine-grafted perfluorosebacic acid (DA₂-PFSEA) and ferric ions by utilizing their coordination interaction. After PEGylation, the obtained fCaCO₃-PEG showed high loading efficacy to perfluoro-15-crown-5-ether (PFCE), a type of perfluorocarbon with high oxygen solubility, thereby working as both oxygen nanoshuttles and proton sponges to reverse tumor hypoxia and acidity-induced resistance to radiotherapy. The as-prepared PFCE@fCaCO₃-PEG could not only function as long-circulating oxygen nanoshuttles to attenuate tumor hypoxia but also neutralize the acidic tumor microenvironment by restricting the production of lactic acid and reacting with extracellular protons. As a result, treatment with PFCE@fCaCO₃-PEG could improve the therapeutic outcome of radiotherapy toward two murine tumors with distinct immunogenicity. The PFCE@fCaCO₃-PEG-assisted radiotherapy could also collectively inhibit the growth of unirradiated tumors and reject rechallenged tumors by synergistically eliciting protective antitumor immunity. Therefore, our work presents the preparation of fluorinated CaCO₃ nanoregulators to reverse tumor immunosuppression and potentiate radiotherapy through chemically modulating tumor hypoxic and acidic microenvironments tightly associated with tumor glucose metabolism.

The emergence of nanoporous materials in lung cancer therapy

Lung cancer is one of the most common cancers, affecting more than 2.1 million people across the globe every year. A very high occurrence and mortality rate of lung cancer have prompted active research in this area with both conventional and novel forms of therapies including the use of nanomaterials based drug delivery agents. Specifically, the unique physico-chemical and biological properties of porous nanomaterials have gained significant momentum as drug delivery agents for delivering a combination of drugs or merging diagnosis with targeted therapy for cancer treatment. This review focuses on the emergence of nano-porous materials for drug delivery in lung cancer. The review analyses the currently used nanoporous materials, including inorganic, organic and hybrid porous materials for delivering drugs for various types of therapies, including chemo, radio and phototherapy. It also analyses the selected research on stimuli-responsive nanoporous materials for drug delivery in lung cancer before summarizing the various findings and projecting the future of emerging trends. This review provides a strong foundation for the current status of the research on nanoporous materials, their limitations and the potential for improving their design to overcome the unique challenges of delivering drugs for the treatment of lung cancer.

Vascular bursts-mediated tumor accumulation and deep penetration of spherical nucleic acids for synergistic radio-immunotherapy

While nanomedicines have attracted great interests for tumor therapy, their targeting and intra-tumoral penetrating efficiencies have been questioned. Here, we report a two-step low-dose radiotherapy (RT) strategy to realize significant accumulation and deep penetration of spherical nucleic acids (SNAs)-based nanomedicine for synergistic radio-immunotherapy. The first step RT was employed to recruit large amounts of macrophages into tumor. The tumor infiltrated macrophages not only served as nanoparticles drug depots, but also elicited dynamic bursts extravasation to enhance nanoparticles accumulation. We optimized the spatiotemporal combination of RT and SNAs administration for higher level of SNAs delivery, and the delivered SNAs promote M2-to-M1 phenotype switch of macrophages to increase phagocytosis of nanoparticles by 6-fold, resulting in positive feedback with even higher accumulation and intra-tumor penetration of SNAs. Through vascular bursts and macrophage repolarization, as high as 25-fold enhancement of nanoparticles accumulation was achieved as compared to passive targeting of nanoparticles, and the nanoparticles were eventually distributed throughout the tumor tissue with efficient deep penetration. Finally, SNAs in tumor simultaneously sensitized the second dose of RT and remodeled tumor immune microenvironment, resulting in a synergistic anticancer therapy in combination of anti-PD-L1 antibody (αPD-L1) with no noticeable side effects caused by either RT or αPD-L1.

Stimuli-Responsive Nanoparticles for Controlled Drug Delivery in Synergistic Cancer Immunotherapy

Cancer immunotherapy has achieved promising clinical progress over the recent years for its potential to treat metastatic tumors and inhibit their recurrences effectively. However, low patient response rates and dose-limiting toxicity remain as major dilemmas for immunotherapy. Stimuli-responsive nanoparticles (srNPs) combined with immunotherapy offer the possibility to amplify anti-tumor immune responses, where the weak acidity, high concentration of glutathione, overexpressions of enzymes, and reactive oxygen species, and external stimuli in tumors act as triggers for controlled drug release. This review highlights the design of srNPs based on tumor microenvironment and/or external stimuli to combine with different anti-tumor drugs, especially the immunoregulatory agents, which eventually realize synergistic immunotherapy of malignant primary or metastatic tumors and acquire a long-term immune memory to prevent tumor recurrence. The authors hope that this review can provide theoretical guidance for the construction and clinical transformation of smart srNPs for controlled drug delivery in synergistic cancer immunotherapy.

Supramolecular Radiosensitizer Based on Hypoxia-Responsive Macrocycle

Radiotherapy (RT) has been viewed as one of the most effective and extensively applied curatives in clinical cancer therapy. However, the radioresistance of tumor severely discounts the radiotherapy outcomes. Here, an innovative supramolecular radiotherapy strategy, based on the complexation of a hypoxia-responsive macrocycle with small-molecule radiosensitizer, is reported. To exemplify this tactic, a carboxylated azocalix[4]arene (CAC4A) is devised as molecular container to quantitatively package tumor sensitizer banoxantrone dihydrochloride (AQ4N) through reversible host-guest interaction. Benefited from the selective reduction of azo functional groups under hypoxic microenvironment, the supramolecular prodrug CAC4A•AQ4N exhibits high tumor accumulation and efficient cellular internalization, thereby significantly amplifying radiation-mediated tumor destruction without appreciable systemic toxicity. More importantly, this supramolecular radiotherapy strategy achieves an ultrahigh sensitizer enhancement ratio (SER) value of 2.349, which is the supreme among currently reported noncovalent-based radiosensitization approach. Further development by applying different radiosensitizing drugs can make this supramolecular strategy become a general platform for boosting therapeutic effect in cancer radiotherapies, tremendously promising for clinical translation.

The application of immune checkpoint blockade in breast cancer and the emerging role of nanoparticle

Breast cancer is the most common malignancy in the female population with a high mortality rate. Despite the satisfying depth of studies evaluating the contributory role of immune checkpoints in this malignancy, few articles have reviewed the pros and cons of immune checkpoint blockades (ICBs). In the current review, we provide an overview of immune-related inhibitory molecules and also discuss the original data obtained from international research laboratories on the aberrant expression of T and non-T cell-associated immune checkpoints in breast cancer. Then, we especially focus on recent studies that utilized ICBs as the treatment strategy in breast cancer and provide their efficiency reports. As there are always costs and benefits, we discuss the limitations and challenges toward ICB therapy such as adverse events and drug resistance. In the last section, we allocate an overview of the recent data concerning the application of nanoparticle systems for cancer immunotherapy and propose that nano-based ICB approaches may overcome the challenges related to ICB therapy in breast cancer. In conclusion, it seems it is time for nanoscience to more rapidly move forward into clinical trials and illuminates the breast cancer treatment area with its potent features for the target delivery of ICBs.

TGF‑β inhibitor RepSox suppresses osteosarcoma via the JNK/Smad3 signaling pathway

Osteosarcoma (OS) is the most common malignant bone tumor and the long-term survival rates remain unsatisfactory. Transforming growth factor-β (TGF-β) has been revealed to play a crucial role in OS progression, and RepSox is an effective TGF-β inhibitor. In the present study, the effect of RepSox on the proliferation of the OS cell lines (HOS and 143B) was detected. The results revealed that RepSox effectively inhibited the proliferation of OS cells by inducing S-phase arrest and apoptosis. Moreover, the inhibitory effect of RepSox on cell migration and invasion was confirmed by wound-healing and Transwell assays. Furthermore, western blotting revealed that the protein levels of molecules associated with the epithelial-mesenchymal transition (EMT) phenotype, including E-cadherin, N-cadherin, Vimentin, matrix metalloproteinase (MMP)-2 and MMP-9, were reduced by RepSox treatment. Concurrently, it was also revealed that the JNK and Smad3 signaling pathway was inhibited. Our in vivo findings using a xenograft model also revealed that RepSox markedly inhibited the growth of tumors. In general, our data demonstrated that RepSox suppressed OS proliferation, EMT and promoted apoptosis by inhibiting the JNK/Smad3 signaling pathway. Thus, RepSox may be a potential anti-OS drug.

Emerging strategies based on nanomaterials for ionizing radiation-optimized drug treatment of cancer

Drug-radiotherapy is a common and effective combinational treatment for cancer. This study aimed to explore the ionizing radiation-optimized drug treatment based on nanomaterials so as to improve the synergistic efficacy of drug-radiotherapy against cancer and limit the adverse effect on healthy organs. In this review, these emerging strategies were divided into four parts. First, the delivery of the drug-loaded nanoparticles was optimized owing to the strengthened passive targeting process, active targeting process, and cell targeting process of nanoparticles after ionizing radiation exposure. Second, nanomaterials were designed to respond to the ionizing radiation, thus leading to the release of the loading drugs controllably. Third, radiation-activated pro-drugs were loaded onto nanoparticles for radiation-triggered drug therapy. In particular, nontoxic nanoparticles with radiosensitization capability and innocuous radio-dynamic contrast agents can be considered as radiation-activated drugs, which were discussed in this review. Fourth, according to the various synergetic mechanisms, radiotherapy could improve the drug response of cancer, obtaining optimized drug-radiotherapy. Finally, relative suggestions were provided to further optimize these aforementioned strategies. Therefore, a novel topic was selected and the emerging strategies in this region were discussed, aiming to stimulate the inspiration for the development of ionizing radiation-optimized drug treatment based on nanomaterials.

Delivery of nanoparticle antigens to antigen-presenting cells: from extracellular specific targeting to intracellular responsive presentation

An appropriate delivery system can improve the immune effects of antigens against various infections or tumors. Antigen-presenting cells (APCs) are specialized to capture and process antigens in vivo, which link the innate and adaptive immune responses. Functionalization of vaccine delivery systems with targeting moieties to APCs is a promising strategy for provoking potent immune responses. Additionally, the internalization and intracellular distribution of antigens are closely related to the initiation of downstream immune responses. With a deeper understanding of the intracellular microenvironment and the mechanisms of antigen presentation, vehicles designed to respond to endogenous and external stimuli can modulate antigen processing and presentation pathways, which are critical to the types of immune response. Here, an overview of extracellular targeting delivery of antigens to APCs and intracellular stimulus-responsiveness strategies is provided, which might be helpful for the rational design of vaccine delivery systems.

Formulation and clinical perspectives of inhalation-based nanocarrier delivery: a new archetype in lung cancer treatment

Despite tremendous research in targeted delivery and specific molecular inhibitors (gene delivery), cytotoxic drug delivery through inhalation has been seen as a core part in the treatment of the lung cancer. Inhalation delivery provides a high dose of the drug directly to the lungs without affecting other body organs, increasing the therapeutic ratio. This article reviews the research performed over the last several decades regarding inhalation delivery of various cancer therapeutics for the treatment of lung cancer. Nevertheless, pulmonary administration of nanocarrier-based cancer therapeutics for lung cancer therapy is still in its infancy and faces greater than expected challenges. This article focuses on the current inhalable nanocarrier-based drugs for lung cancer treatment.

Combining Mechanical High-Intensity Focused Ultrasound Ablation with Chemotherapy for Augmentation of Anticancer Immune Responses

As a noninvasive therapy, high-intensity focused ultrasound (HIFU) shows great potential in inducing anticancer immune responses. However, the overall anticancer efficacy of HIFU is still limited due to the rapid attenuation of ultrasound waves and inadequacy of ultrasound waves to spread to the whole tumor. Here, we combined HIFU with the ultrasound contrast agent/chemotherapeutic drug co-delivery nanodroplets to achieve synergistic enhancement of anticancer efficacy. Different from the widely used thermal HIFU irradiation, by which excessive heating would result in inactivation of immune stimulatory molecules, we used short acoustic pulses to trigger HIFU (mechanical HIFU, mHIFU) to improve anticancer immune responses. The nanodroplets displayed a mHIFU/glutathione (GSH)-dual responsive drug release property, and their cellular uptake efficacy and toxicity against cancer cells increased upon mHIFU irradiation. The generated immunogenic debris successfully induced the exposure of damage-associated molecular patterns on the cell surface for dendritic cells (DCs) maturation. In vivo experiments with tumor-bearing mice showed that the co-delivery nanodroplets in combination with mHIFU could effectively inhibit tumor growth by inducing immunogenic cell death, activating DCs maturation, and enhancing the effector T-cell infiltration within tumors. This work reveals that combined treatment with nanodroplets and mHIFU is a promising approach to eradicate tumors.

Nanoparticle-mediated tumor vaccines for personalized therapy: preparing tumor antigens in vivo or ex vivo?

Tumor vaccines, focusing on tailoring individual tumor antigens, have gained much attention in personalized tumor therapy. Recently, breakthroughs have been made in the development of tumor vaccines thanks to the progress in nanotechnology. We will summarize nanoparticle-mediated tumor vaccines for personalized therapy in this review. ROS/heat generating nanoparticles and molecules could induce immunogenic cell death and tumor antigen release in vivo. This strategy often includes chemotherapy, radiotherapy, photodynamic therapy, photothermal therapy, magneto-thermal therapy, etc. On the other hand, ex vivo technologies have been applied for processing of tumor cells/tissues to form effective tumor antigens, in which nanotechnology has shown very good prospects in delivering tumor antigens. In in vivo and ex vivo strategies, nanotechnology also could improve the immune effect through enhancing the uptake by targeting cells, reducing therapeutic drugs/agents, further encapsulating immuno-modulatory molecules or combining with other therapy treatments. Thus, therapeutic vaccines based on nanoparticles have the potential to enhance the immune response and reduce the side effects.

Hybrid Hierarchical Heterostructures of Nanoceramic Phosphors as Imaging Agents for Multiplexing and Living Cancer Cells Translocation

Existing fluorescent labels used in life sciences are based on organic compounds with limited lifetime or on quantum dots which are either expensive or toxic and have low kinetic stability in biological environments. To address these challenges, luminescent nanomaterials have been conceived as hierarchical, core–shell structures with spherical morphology and highly controlled dimensions. These tailor-made nanophosphors incorporate Ln:YVO₄ nanoparticles (Ln = Eu(III) and Er(III)) as 50 nm cores and display intense and narrow emission maxima centered at ∼565 nm. These cores can be encapsulated in silica shells with highly controlled dimensions as well as functionalized with chitosan or PEG5000 to reduce nonspecific interactions with biomolecules in living cells. Confocal fluorescence microscopy in living prostate cancer cells confirmed the potential of these platforms to overcome the disadvantages of commercial fluorophores and their feasibility as labels for multiplexing, biosensing, and imaging in life science assays.

Oxygen-Enriched Metal-Phenolic X-Ray Nanoprocessor for Cancer Radio-Radiodynamic Therapy in Combination with Checkpoint Blockade Immunotherapy

Radiotherapy (RT) based on DNA damage and reactive oxygen species (ROS) generation has been clinically validated in various types of cancer. However, high dose-dependent induced toxicity to tissues, non-selectivity, and radioresistance greatly limit the application of RT. Herein, an oxygen-enriched X-ray nanoprocessor Hb@Hf-Ce6 nanoparticle is developed for improving the therapeutic effect of RT-radiodynamic therapy (RDT), enhancing modulation of hypoxia tumor microenvironment (TME) and promoting antitumor immune response in combination with programmed cell death protein 1 (PD-1) immune checkpoint blockade. All functional molecules are integrated into the nanoparticle based on metal-phenolic coordination, wherein one high-Z radiosensitizer (hafnium, Hf) coordinated with chlorin e6 (Ce6) modified polyphenols and a promising oxygen carrier (hemoglobin, Hb) is encapsulated for modulation of oxygen balance in the hypoxia TME. Specifically, under single X-ray irradiation, radioluminescence excited by Hf can activate photosensitizer Ce6 for ROS generation by RDT. Therefore, this combinatory strategy induces comprehensive antitumor immune response for cancer eradication and metastasis inhibition. This work presents a multifunctional metal-phenolic nanoplatform for efficient X-ray mediated RT-RDT in combination with immunotherapy and may provide a new therapeutic option for cancer treatment.

Recent Advances in Hyperthermia Therapy-Based Synergistic Immunotherapy

The past decades have witnessed hyperthermia therapy (HTT) as an emerging strategy against malignant tumors. Nanomaterial-based photothermal therapy (PTT) and magnetic hyperthermia (MHT), as highly effective and noninvasive treatment models, offer advantages over other strategies in the treatment of different types of tumors. However, both PTT and MHT cannot completely cure cancer due to recurrence and distal metastasis. In recent years, cancer immunotherapy has attracted widespread attention owing to its capability to activate the body's own natural defense to identify, attack, and eradicate cancer cells. Significant efforts have been devoted to studying the activated immune responses caused by hyperthermia-ablated tumors. In this article, the synergistic mechanism of HTT in immunotherapy, including immunogenic cell death and reversal of the immunosuppressive tumor microenvironment is discussed. The reports of the combination of HTT or HTT-based multimodal therapy with immunotherapy, including immunoadjuvant exploitation, immune checkpoint blockade therapy, and adoptive cellular immunotherapy are summarized. As highlighted, these strategies could achieve synergistically enhanced therapeutic outcomes against both primary tumors and metastatic lesions, prevent cancer recurrence, and prolong the survival period. Finally, current challenges and prospective developments in HTT-synergized immunotherapy are also reviewed.

Biomimetic Anti-PD-1 Peptide-Loaded 2D FePSe3 Nanosheets for Efficient Photothermal and Enhanced Immune Therapy with Multimodal MR/PA/Thermal Imaging

Metal phosphorous trichalcogenides (MPX3) are novel 2D nanomaterials that have recently been exploited as efficient photothermal-chemodynamic agents for cancer therapy. As a representative MPX3, FePSe3 has the potential to be developed as magnetic resonance imaging (MRI) and photoacoustic imaging (PAI) agents due to the composition of Fe and the previously revealed PA signal. Here, a FePSe3-based theranostic agent, FePSe3@APP@CCM, loaded with anti-PD-1 peptide (APP) as the inner component and CT26 cancer cell membrane (CCM) as the outer shell is reported, which acts as a multifunctional agent for MR and PA imaging and photothermal and immunotherapy against cancer. FePSe3@APP@CCM induces highly efficient tumor ablation and suppresses tumor growth by photothermal therapy under near-infrared laser excitation, which further activates immune responses. Moreover, APP blocks the PD-1/PD-L1 pathway to activate cytotoxic T cells, causing strong anticancer immunity. The combined therapy significantly prolongs the lifespan of experimental mice. The multimodal imaging and synergistic therapeutic effects of PTT and its triggered immune responses and APP-related immunotherapy are clearly demonstrated by in vitro and in vivo experiments. This work demonstrates the potential of MPX3-based biomaterials as novel theranostic agents.

Implantable and Injectable Biomaterial Scaffolds for Cancer Immunotherapy

Cancer immunotherapy has become an emerging strategy recently producing durable immune responses in patients with varieties of malignant tumors. However, the main limitation for the broad application of immunotherapies still to reduce side effects by controlling and regulating the immune system. In order to improve both efficacy and safety, biomaterials have been applied to immunotherapies for the specific modulation of immune cells and the immunosuppressive tumor microenvironment. Recently, researchers have constantly developed biomaterials with new structures, properties and functions. This review provides the most recent advances in the delivery strategies of immunotherapies based on localized biomaterials, focusing on the implantable and injectable biomaterial scaffolds. Finally, the challenges and prospects of applying implantable and injectable biomaterial scaffolds in the development of future cancer immunotherapies are discussed.

Perspectives of Methotrexate-Based Radioagents for Application in Nuclear Medicine

Methotrexate is a gold standard among disease modifying antirheumatic drugs and is also extensively used clinically in combination with oncological therapies. Thus, it is not surprising that nuclear medicine found an interest in methotrexate in the search for diagnostic and therapeutic solutions. Numerous folate-related radiopharmaceuticals have been proposed for nuclear medicine purposes; however, methotrexate radioagents represent only a minority. This imbalance results from the fact that methotrexate has significantly weaker affinity for folate receptors than folic acid. Nevertheless, radiolabeled methotrexate agents utilized as a tool for early detection and imaging of inflammation in rheumatoid arthritis patients gave promising results. Similarly, the use of multimodal MTX-release nanosystems may find potential applications in radiosynovectomy and theranostic approaches in folate receptor positive cancers.

Design, Bioanalytical, and Biomedical Applications of Aptamer-Based Hydrogels

Aptamers are special types of single-stranded DNA generated by a process called systematic evolution of ligands by exponential enrichment (SELEX). Due to significant advances in the chemical synthesis and biotechnological production, aptamers have gained considerable attention as versatile building blocks for the next generation of soft materials. Hydrogels are high water-retainable materials with a three-dimensional (3D) polymeric network. Aptamers, as a vital element, have greatly expanded the applications of hydrogels. Due to their biocompatibility, selective binding, and molecular recognition, aptamer-based hydrogels can be utilized for bioanalytical and biomedical applications. In this review, we focus on the latest strategies of aptamer-based hydrogels in bioanalytical and biomedical applications. We begin this review with an overview of the underlying design principles for the construction of aptamer-based hydrogels. Next, we will discuss some bioanalytical and biomedical applications of aptamer-based hydrogel including biosensing, target capture and release, logic devices, gene and cancer therapy. Finally, the recent progress of aptamer-based hydrogels is discussed, along with challenges and future perspectives.

Simultaneously boosting the conjugation, brightness and solubility of organic fluorophores by using AIEgens

Organic near-infrared (NIR) emitters hold great promise for biomedical applications. Yet, most organic NIR fluorophores face the limitations of short emission wavelengths, low brightness, unsatisfactory processability, and the aggregation-caused quenching effect. Therefore, development of effective molecular design strategies to improve these important properties at the same time is a highly pursued topic, but very challenging. Herein, aggregation-induced emission luminogens (AIEgens) are employed as substituents to simultaneously extend the conjugation length, boost the fluorescence quantum yield, and increase the solubility of organic NIR fluorophores, being favourable for biological applications. A series of donor-acceptor type compounds with different substituent groups (i.e., hydrogen, phenyl, and tetraphenylethene (TPE)) are synthesized and investigated. Compared to the other two analogs, MTPE-TP3 with TPE substituents exhibits the reddest fluorescence, highest brightness, and best solubility. Both the conjugated structure and twisted conformation of TPE groups endow the resulting compounds with improved fluorescence properties and processability for biomedical applications. The in vitro and in vivo applications reveal that the NIR nanoparticles function as a potent probe for tumour imaging. This study would provide new insights into the development of efficient building blocks for improving the performance of organic NIR emitters.