Immune Complexes Mimicking Synthetic Vaccine Nanoparticles for Enhanced Migration and Cross‐Presentation of Dendritic Cells

The well‐designed activation of dendritic cells (DCs) by enhancing the delivery of antigens and immunostimulatory adjuvants into DCs is a key strategy for efficient cancer immunotherapy. Antigen‐antibody immune complexes (ICs) are known to directly bind to and cross‐link Fc‐gamma receptors (FcγRs) on DCs, which induce enhanced migration of DCs to draining lymph nodes through the up‐regulation of the chemokine receptor CCR7 and cross‐presentation inducing cytotoxic T lymphocyte (CTL) response against tumor antigen. In this study, ICs mimicking synthetic vaccine nanoparticles (NPs) are designed and synthesized by the coating of poly (lactic‐co‐glycolic acid) (PLGA) NPs containing adjuvant (CpG oligodeoxynuleotides (ODNs) as toll‐like receptor 9 ligands) with ovalbumin (OVA) proteins (as model antigens) and by the formation of OVA–OVA antibody ICs. Through the combination of FcγRs‐mediated efficient antigen uptake and CpG ODNs‐based immunostimulation, the secretion of TNF‐α (12.3‐fold), IL‐6 (7.29‐fold), and IL‐12 (11‐fold), homing ability to lymph nodes (7.5‐fold), and cross‐presentation (83.8‐fold IL‐2 secretion) are dramatically increased in DCs treated with PLGA(IC/CpG) NPs. Furthermore, mice vaccinated with DCs treated with PLGA(IC/CpG) NPs induced significant tumor (EG7‐OVA) growth inhibition as well as prolonged survival through CTL‐mediated enhanced cytotoxicity, antigen‐specific responses, and IFN‐γ secretion.     

Surface Engineered Polymersomes for Enhanced Modulation of Dendritic Cells During Cardiovascular Immunotherapy

The principle cause of cardiovascular disease (CVD) is atherosclerosis, a chronic inflammatory condition characterized by immunologically complex fatty lesions within the intima of arterial vessel walls. Dendritic cells (DCs) are key regulators of atherosclerotic inflammation, with mature DCs generating pro‐inflammatory signals within vascular lesions and tolerogenic DCs eliciting atheroprotective cytokine profiles and regulatory T‐cell (Treg) activation. Here, the surface chemistry and morphology of synthetic nanocarriers composed of poly(ethylene glycol)‐b‐poly(propylene sulfide) copolymers to enhance the targeted modulation of DCs by transporting the anti‐inflammatory agent 1,25‐dihydroxyvitamin D3‐(aVD) and ApoB‐100‐derived antigenic peptide P210 are engineered. Polymersomes decorated with an optimized surface display and density for a lipid construct of the P‐D2 peptide, which binds CD11c on the DC surface, significantly enhance the cytosolic delivery and resulting immunomodulatory capacity of aVD in vitro. Weekly low‐dose intravenous administration of DC‐targeted, aVD‐loaded polymersomes significantly inhibit atherosclerotic lesion development in high‐fat‐diet‐fed ApoE^?/? mice. The results validate the key role of DC immunomodulation during aVD‐dependent inhibition of atherosclerosis and demonstrate the therapeutic enhancement and dosage lowering capability of cell‐targeted nanotherapy in the treatment of CVD.     

Cationic Lipids-Mediated Dual-Targeting of Both Dendritic Cells and Tumor Cells for Potent Cancer Immunotherapy

Impaired antigen presentation either in dendritic cells (DCs) or tumor cells impedes the triggering of antitumor immunity or tumor cell killing, resulting in failures of multiple types of cancer immunotherapy. Herein, the strategy of using dual-targeting nanomedicines to simultaneously improve the presentation of tumor antigens by both DCs and tumor cells is proposed. It is shown that tuning of surface charge of nanoparticles (NPs) by incorporating different amounts of cationic lipids alters the in vivo NP tissue accumulation and cellular targeting profiles. NPs with moderately positive surface charge (≈20 mV) achieve efficient accumulation in tumors and lymph nodes and dual-targeting to both DCs and tumor cells. As a proof-of-concept demonstration, siRNA against YTH N6−methyladenosine RNA binding protein 1 (YTHDF1) is delivered by the dual-targeting NPs to inhibit excessive antigen degradation in both DCs and tumor cells. For DCs, YTHDF1 downregulation promotes tumor antigen cross-presentation and cross-priming of antigen-specific T cells. For tumor cells, it enhances the presentation of endogenous tumor antigens and hence improves both the recognition and killing of tumor cells by primed antigen-specific T cells. The dual-targeting nanomedicines generate efficient antitumor immunity.     

Nanovaccine-Mediated Cell Selective Delivery of Neoantigens Potentiating Adoptive Dendritic Cell Transfer for Personalized Immunization

Neoantigen vaccines and adoptive dendritic cell (DC) transfer are major clinical approaches to initiate personalized immunity in cancer patients. However, the immunization efficacy is largely limited by the in vivo trajectory including neoantigens’ access to resident DCs and DCs’ access to lymph nodes (LNs). Herein, an innovative strategy is proposed to improve personalized immunization through neoantigen-loaded nanovaccines synergized with adoptive DC transfer. It is found that it enables selective delivery of neoantigens to resident DCs and macrophages by coating cancer cell membranes onto neoantigen-loaded nanoparticles. In addition, the nanovaccines promote the secretion of chemokine C-C motif ligand 2 (CCL2), CCL3, and C-X-C motif ligand 10 from macrophages, thus potentiating the access of transferred DCs to LNs. This immunization strategy enables coordinated delivery of identified neoantigens and autologous tumor lysate-derived undefined antigens, leading to initiation of antitumor T cell immunity in a personalized manner. It significantly inhibits tumor growth in prophylactic and established mouse tumor models. The findings provide a new vision for potentiating adoptive cell transfer by nanovaccines, which may open the door to a transformative possibility for improving personalized immunization.     

Local Immune‐Triggered Surface‐Modified Stem Cells for Solid Tumor Immunotherapy

Here, described are additional treatment strategies that make use of human mesenchymal stem cell (hMSC)‐based local immunotherapeutic agents for the treatment of solid tumors. Dibenzocyclooctyne‐poly(ethylene glycol)‐pheophorbide A conjugates are engineered for cell surface conjugation by copper‐free click chemistry and are subsequently conjugated to hMSC (hMSC‐DPP). hMSC‐DPP can recognize and migrate toward cancer lesions, where they secrete pro‐inflammatory cytokines such as interleukin (IL)‐6, IL‐8, and heat shock protein 70 in pursuance of photodynamic therapy‐mediated cell death. The secreted immune factors trigger interferon gamma, IL‐2, IL‐4, IL‐12, and granulocyte‐macrophage colony‐stimulating factor, resulting in the local accumulation of T cells, B cells, natural killer cells, and antigen presenting cells at the tumor site. Treatment with hMSC‐DPP induces the accumulation of cytokines at the cancer site and minimizes systemic immune‐based side effects. This strategy is expected to increase the vulnerability of cancer cells to immune cells and cytokines, thus aiding in the development of a robust treatment platform for cancer immunotherapy.     

Modulation of Dendritic Cells by Lipid Grafted Polyelectrolyte Microcapsules

Polyelectrolyte microcapsules are fabricated by layer‐by‐layer deposition of dextran sulfate and poly‐L ‐arginine layers at the surface of calcium carbonate template microparticles followed by core removal to produce hollow microcapsules. In the context of vaccination, these biodegradable LbL capsules emerge as promising antigen carriers and are believed to have potential for the co‐delivery of antigens and immunomodulators associated within the same particle to enhance and steer the type of immune response. To this end, it is shown that LbL microcapsules can be functionalized at their surface with lipid layers containing immunopotentiators of lipid nature. The potency of the different lipid modified microcapsules to activate dendritic cells (DCs) is demonstrated by increased expression levels of the migration marker CCR7 and the maturation markers CD40 and CD86. Additionally, the DCs cytokine secretion profile is evaluated. The findings reveal that the lipid grafted microcapsules are superior to non‐modified microcapsules in DC activation and suggest their potential as immune modulating antigen delivery systems.     

Nanomaterials for Combinational Radio–Immuno Oncotherapy

Radiotherapy, a clinically used local treatment modality of cancers, is regarded as a promising candidate to promote current immunotherapy through initiating an in situ vaccination effect and reprogramming the immunosuppressive microenvironment. The combination of radiotherapy and immunotherapy, referred to as combinational radio–immuno oncotherapy (CRIOT), elicits a synergistic antitumor effect based on the immunomodulatory properties of radiation. Unfortunately, current CRIOT accompanies low response rate and severe toxicity in clinical trials, thus limiting its application. To this end, various nanomaterials are being developed to sensitize radiotherapy or deliver immune agents, or both, to improve the unsatisfactory outcomes of CRIOT. Herein, enhanced antitumor efficacy of CRIOT with nanomaterials through the possible mechanisms of rejuvenation and activation of T cells, increased presentation of tumor‐related antigens, and inhibition of suppressive macrophages is presented, and the prospect of CRIOT in clinical practice is proposed.     

树突状细胞分化模型在人工免疫系统中的应用研究

 树突状细胞(Dendritic Cell,DC)是先天性免疫系统的重要组件,其分化机制是正确引发与调节适应性免疫响应的关键.首先,在描述DC分化的生物机理基础上,抽象出了DC的信息处理过程.其次,在阐释DAMP等四类外部信号的含义与功能、信号融合过程的基础上,定义了未成熟、完全成熟与半成熟DC Agent,刻画了它们的分化数学模型与演化过程.最后,论证了各类DC Agent数量与生存周期之间的关系.实验结果表明DC分化机制对降低入侵检测误报率、实现自我调节和进一步增强计算机系统安全具有重要的理论意义与应用价值.     

Interaction of Human Mesenchymal Stem Cells with Soft Nanocomposite Hydrogels Based on Polyethylene Glycol and Dendritic Polyglycerol

Keeping the stemness of human mesenchymal stem cells (hMSCs) and their adipocyte differentiation potential is critical for clinical use. However, these features are lost on traditional substrates. hMSCs have often been studied on stiff materials whereas culturing hMSCs in their native niche increases their potential. Herein, a patterned hydrogel nanocomposite with the stiffness of liver tissues is obtained without any molding process. To investigate hMSCs' mechanoresponse to the material, the RGD spacing units and the stiffness of the hydrogels are dually tuned via the linker length. This work suggests that hMSCs' locomotion is influenced by the nature of the hydrogel layer (bulk or thin film). Contrary to on bulk surfaces, cell traction occurs during cell spreading on thin films. In addition, hMSCs' spreading behavior varies from shorter to longer linker‐based hydrogels, where on both surfaces hMSCs maintains their stemness as well as their adipogenic differentiation potential with a higher number of adipocytes for nanocomposites with a longer polymer linker. Overall, this work addresses the need for a new alternative for hMSCs culture allowing the cells to differentiate exclusively into adipocytes. This material represents a cell‐responsive platform with a tissue‐mimicking architecture given by the mechanical and morphological properties of the hydrogel.     

Poly(cyclodextrin)‐Polydrug Nanocomplexes as Synthetic Oncolytic Virus for Locoregional Melanoma Chemoimmunotherapy

Despite the approval of oncolytic virus (OV) therapy for advanced melanoma, its intrinsic limitations that include the risk of persistent viral infection and cost‐intensive manufacturing motivate the development of analogous approaches that are free from the disadvantages of virus‐based therapies. Herein, reported is a nanoassembly comprised of multivalent host–guest interactions between polymerized paclitaxel (pPTX) and nitric oxide‐incorporated polymerized β‐cyclodextrin (pCD‐pSNO) that through its bioactive components and when used locoregionally recapitulates the therapeutic effects of OV. The resultant pPTX/pCD‐pSNO exhibits significantly enhanced cytotoxicity, immunogenic cell death, dendritic cell (DC) activation, and T cell expansion in vitro compared to free agents alone or in combination. In vivo, intratumoral administration of pPTX/pCD‐pSNO results in activation and expansion of DCs systemically, but with a corresponding expansion of myeloid‐derived suppressor cells and suppression of CD8⁺ T cell expansion. When combined with antibody targeting cytotoxic T lymphocyte antigen‐4 that blunts this molecule's signaling effects on T cells, intratumoral pPTX/pCD‐pSNO treatment elicits potent anticancer effects that significantly prolong animal survival. This formulation thus leverages the chemo‐ and immunotherapeutic synergies of PTX and nitric oxide and suggests the potential for virus‐free nanoformulations to mimic the therapeutic action and benefits of OVs.     

iRGD-Liposomes Enhance Tumor Delivery and Therapeutic Efficacy of Antisense Oligonucleotide Drugs against Primary Prostate Cancer and Bone Metastasis

Nucleotide-based drugs, such as antisense oligonucleotides (ASOs), have unique advantages in treating human diseases as they provide virtually unlimited ability to target any gene. However, their clinical translation faces many challenges, one of which is poor delivery to the target tissue in vivo. This problem is particularly evident in solid tumors. Here, liposomes are functionalized with a tumor-homing and -penetrating peptide, iRGD, as a carrier of an ASO against androgen receptor (AR) for prostate cancer treatment. The iRGD-liposomes exhibit a high loading efficiency of AR-ASO, and an efficient knockdown of AR gene products is achieved in vitro, including AR splice variants. In vivo, iRGD-liposomes significantly increase AR-ASO accumulation in the tumor tissue and decrease AR expression relative to free ASOs in prostate tumors established as subcutaneous xenografts. Similar results are obtained with intra-tibial xenografts modeling metastasis to bones, the predominant site of metastasis for prostate cancer. In treatment studies, iRGD-liposomes markedly improve the AR-ASO efficacy in suppressing the growth of both subcutaneous xenografts and intra-tibial xenografts. The inhibitory effect on tumor growth is also significantly prolonged by the delivery of the AR-ASO in the iRGD-liposomes. Meanwhile, iRGD-liposomes does not increase ASO accumulation or toxicity in healthy organs. Overall, a delivery system that can significantly increase ASO accumulation and efficacy in solid tumors is provided here. These benefits are achieved without significant side effects, providing a way to increase the antitumor efficacy of ASOs.     

A Bio‐Inspired Rod‐Shaped Nanoplatform for Strongly Infecting Tumor Cells and Enhancing the Delivery Efficiency of Anticancer Drugs

The rapid clearance of circulating nanocarriers in blood during systemic drug delivery remains a challenging hurdle in cancer chemotherapy. Here, inspired by the unique features of bacterial pathogens, an original biodegradable polymer micellar system with a rod‐like shape similar to the morphology of bacterial pathogens is developed. These novel nanocarriers have excellent features such as a great capacity of overcoming the rapid clearance of reticuloendothelial system (RES) with long blood circulation, high cellular internalization, and enhanced therapeutic efficacy against cancers. In vivo pharmacokinetic studies in mice reveal that the rod‐like micelles of ≈40 nm in diameter and 600 nm in length possess a minimal uptake by the RES and excellent blood circulation half‐lives (t_1/2β = 24.23 ± 2.87 h) for carrying doxorubicin in contrast to spheres (t_1/2β = 8.39 ± 0.53 h). The antitumor activity of the rod‐shaped micelles in Balb/c mice bearing H22 tumor xenograft models reveals that they are promptly internalized by tumor cells, resulting in their superior potency and efficacy against artificial solid tumors. These findings suggest that the bio‐inspired nanocarriers as an emerging drug delivery platform may have considerable benefits for enhancing the delivery efficiency of anticancer drugs and in turn enhancing cancer therapy in future clinical applications.     

Negatively Charged Magnetite Nanoparticle Clusters as Efficient MRI Probes for Dendritic Cell Labeling and In Vivo Tracking

Cell labeling and tracking via magnetic resonance imaging (MRI) has drawn much attention for its noninvasive property and longitudinal monitoring functionality. Employing of imaging probes with high labeling efficiency and good biocompatibility is one of the essential factors that determine the outcome of tracking. In this study, negatively charged superparamagnetic iron oxide (PAsp‐PCL/SPIO) nanoclusters are developed for dendritic cell (DC) labeling and tracking in vivo. PAsp‐PCL/SPIO has a diameter of 124 ± 41 nm in DLS, negatively charged surface (zeta potential = ?27 mV), and presents high T ₂ relaxivity (335.6 Fe mm ^?1 s^?1) and good DC labeling efficiency. Labeled DCs are unaffected in their viability, proliferation, and differentiation capacity, and have an excellent MR imaging sensitivity in vitro. To monitor the migration of DCs into lymphoid tissues in vivo, which will be related to the final immunotherapy results, T ₂‐wighted and T ₂‐map imaging of popliteal nodes at different points in time are acquired under a clinical 3 T scanner after subcutaneous injection of a certain number of labeled DCs at hindleg footpads of mice. The signal intensities decreasing and T ₂ values shortening of ipsilateral popliteal nodes are significant and display a time‐ and dose‐dependence, showing DCs' migration to the draining lymph nodes.     

FAP-Targeted Photodynamic Therapy Mediated by Ferritin Nanoparticles Elicits an Immune Response against Cancer Cells and Cancer Associated Fibroblasts

Cancer-associated fibroblasts (CAFs) are present in many types of tumors and play a pivotal role in tumor progression and immunosuppression. Fibroblast-activation protein (FAP), which is overexpressed on CAFs, has been indicated as a universal tumor target. However, FAP expression is not restricted to tumors, and systemic treatment against FAP often causes severe side effects. To solve this problem, a photodynamic therapy (PDT) approach is developed based on ZnF₁₆Pc-loaded and FAP-specific single chain variable fragment (scFv)-conjugated apoferritin nanoparticles, or αFAP-Z@FRT. αFAP-Z@FRT PDT efficiently eradicates CAFs in tumors without inducing systemic toxicity. When tested in murine 4T1 models, the treatment elicits anti-cancer immunity, causing suppression of both primary and distant tumors, that is, the abscopal effect. Treatment efficacy is enhanced when αFAP-Z@FRT PDT is used in combination with anti-PD1 antibodies. Interestingly, it is found that the PDT treatment not only elicits a cellular immunity against cancer cells, but also stimulates an anti-CAFs immunity. This is supported by an adoptive cell transfer study, where T cells taken from 4T1-tumor-bearing animals treated with αFAP PDT retard the growth of A549 tumors established on nude mice. Overall, this approach is unique for permitting site-specific eradication of CAFs and inducing a broad spectrum anti-cancer immunity.     

Macrophage-Mediated Tumor Cell Phagocytosis: Opportunity for Nanomedicine Intervention

Macrophages are one of the most abundant non-malignant cells in the tumor microenvironment, playing critical roles in mediating tumor immunity. As important innate immune cells, macrophages possess the potential to engulf tumor cells and present tumor-specific antigens for adaptive antitumor immunity induction, leading to growing interest in targeting macrophage phagocytosis for cancer immunotherapy. Nevertheless, live tumor cells have evolved to evade phagocytosis by macrophages via the extensive expression of anti-phagocytic molecules, such as CD47. In addition, macrophages also rapidly recognize and engulf apoptotic cells (efferocytosis) in the tumor microenvironment, which inhibits inflammatory responses and facilitates immune escape of tumor cells. Thus, intervention of macrophage phagocytosis by blocking anti-phagocytic signals on live tumor cells or inhibiting tumor efferocytosis presents a promising strategy for the development of cancer immunotherapies. Here, the regulation of macrophage-mediated tumor cell phagocytosis is first summarized, followed by an overview of strategies targeting macrophage phagocytosis for the development of antitumor therapies. Given the potential off-target effects associated with the administration of traditional therapeutics (for example, monoclonal antibodies and small molecule inhibitors), the opportunity for nanomedicine in macrophage phagocytosis intervention is highlighted.     

Microdevice for Separation of Circulating Tumor Cells Using Embedded Magnetophoresis with V‐shaped Ni‐Co Nanowires and Immuno‐nanomagnetic Beads

The novelty of this study resides in a 6”‐wafer‐level microfabrication protocol for a microdevice with a fluidic control system for the separation of circulating tumor cells (CTCs) from human whole blood cells. The microdevice utilizes a lateral magnetophoresis method based on immunomagnetic nanobeads with anti‐epithelial cell adhesive molecule antibodies that selectively bind to epithelial cancer cells. The device consists of a top polydimethylsiloxane substrate for microfluidic control and a bottom substrate for lateral magnetophoretic force generation with embedded v‐shaped soft magnetic microwires. The microdevice can isolate about 93% of the spiked cancer cells (MCF‐7, a breast cancer cell line) at a flow rate of 40/100 mL/min with respect to a whole human blood/buffer solution. For all isolation, it takes only 10 min to process 400 mL of whole human blood. The fabrication method is sufficiently simple and easy, allowing the microdevice to be a mass‐producible clinical tool for cancer diagnosis, prognosis, and personalized medicine.     

Delivery Techniques for Enhancing CAR T Cell Therapy against Solid Tumors

Chimeric antigen receptor (CAR) T cells exhibit promising results for cancer immunotherapy. However, the clinical success is still restricted to certain types of blood cancers, while in solid tumors the clinical activity is modest and potential toxicities remain a concern. There are various barriers that prevent CAR T cells from combating solid tumors. Therefore, distinct strategies have been explored to augment CAR T cell proliferative capacity, persistence, and effector function. Altering the tumor microenvironment, and in particular its physiochemical properties and immunosuppressive milieu, is of great significance to facilitate CAR T cell therapy. In this article, emerging strategies implemented to overcome the barriers of CAR T cell therapy in solid tumors are reviewed. Enhancing infiltration, activation, and persistence of CAR T cells has been addressed in several preclinical models. The future development of this field to promote innovation and clinical translation is also discussed.     

Enhanced Specificity in Capturing and Restraining Circulating Tumor Cells with Dual Antibody–Dendrimer Conjugates

Specifically capturing and restraining residual circulating tumor cells (CTCs) in cancer patients are the sine qua non for safely and effectively preventing cancer metastasis, to which the current chemotherapy has been limited due to its toxicity. Moreover, because of CTCs’ rarity and low activity, the current technology for capturing CTCs based solely on a single surface biomarker has limited capacity and is used mainly for in vitro diagnosis. Here, it is possible to sequentially conjugate two CTCs antibodies (aEpCAM and aSlex) to the functionalized dendrimers to specifically capture human hepatocellular CTCs in both artificial and clinical patient blood samples, and restrain their activities. The molecular entities of the conjugates are demonstrated by various means. The dual antibody conjugate captured CTCs threefold more than the single counterparts from the high concentrations of interfering red blood cells or leukocytes, as well as from the blood of liver cancer patients, and exhibits the superiority to their single counterparts in down‐regulating the captured CTCs. These results collectively provide the strong evidence that two antibodies can be compatibly conjugated to a nanomaterial, resulting in an enhanced specificity in restraining CTCs in blood.     

Nanotechnology-Based CAR-T Strategies for Improving Efficacy and Safety of Tumor Immunotherapy

Therapeutic responses to chimeric antigen receptor (CAR) T cell therapy in patients with limited treatment options have been appealing in several clinical trials. However, the efficacy of CAR-T therapy has been challenged by several obstacles when treating patients with solid tumors, such as severe toxicities, restricted access to tumor sites, suboptimal therapeutic persistence, and manufacturing issues. Nanotechnology has the advantages of protecting CAR-T cells from being suppressed by tumor microenvironment (TME) and favorably adapting immune-modulating drugs’ pharmacokinetics by modifying their spatiotemporal release profiles. Loaded with nanoparticles and packed onto CAR-T cells, immune-modulating drugs can be delivered to the tumor site and lymph node more efficiently, stimulating the expansion and activity of CAR-T cells. To protect normal tissues from the nonspecific toxicity of the activated CAR-T cells, formulations are optimized toward tumor targeting delivery of nanotechnology. This review summarizes the nanotechnology strategies to improve the safety and efficacy of CAR-T therapy. In addition, the unsolved problems existing in the clinical application of CAR-T therapy are focused on, where study and exploration by the way of nanotechnology is needed.