"Minimalist" Nanovaccine Constituted from Near Whole Antigen for Cancer Immunotherapy

Extracellular Vesicle-Inspired Minimalist Flexible Nanocapsules Assembled with Whole Active Ingredients for Highly Efficient Enhancement of DC-Mediated Tumor Immunotherapy

The development of nanovaccines capable of eliciting tumor-specific immune responses holds significant promise for tumor immunotherapy. However, many nanovaccine designs rely heavily on incorporating multiple adjuvants and carriers, increasing the biological hazards associated with these additional components. Here, this work introduces novel flexible nanocapsules (OVAnano) designed to mimic extracellular vesicles, primarily using the ovalbumin antigen and minimal polyethylenimine adjuvant components. These results show that the biomimetic flexible structure of OVAnano facilitates enhanced antigen uptake by dendritic cells (DCs), leading to efficient antigen and adjuvant release into the cytosol via endosomal escape, and ultimately, successful antigen cross-presentation by DCs. Furthermore, OVAnano modulates the intracellular nuclear factor kappa-B (NF-κB) signaling pathway, promoting DC maturation. The highly purified antigens in OVAnano demonstrate remarkable antigen-specific immunogenicity, triggering strong antitumor immune responses mediated by DCs. Therapeutic tumor vaccination studies have also shown that OVAnano administration effectively suppresses tumor growth in mice by inducing immune responses from CD8+ and CD4+ T cells targeting specific antigens, reducing immunosuppression by regulatory T cells, and boosting the populations of effector memory T cells. These findings underscore that the simple yet potent strategy of employing minimal flexible nanocapsules markedly enhances DC-mediated antitumor immunotherapy, offering promising avenues for future clinical applications.

Engineering customized nanovaccines for enhanced cancer immunotherapy

Nanovaccines have gathered significant attention for their potential to elicit tumor-specific immunological responses. Despite notable progress in tumor immunotherapy, nanovaccines still encounter considerable challenges such as low delivery efficiency, limited targeting ability, and suboptimal efficacy. With an aim of addressing these issues, engineering customized nanovaccines through modification or functionalization has emerged as a promising approach. These tailored nanovaccines not only enhance antigen presentation, but also effectively modulate immunosuppression within the tumor microenvironment. Specifically, they are distinguished by their diverse sizes, shapes, charges, structures, and unique physicochemical properties, along with targeting ligands. These features of nanovaccines facilitate lymph node accumulation and activation/regulation of immune cells. This overview of bespoke nanovaccines underscores their potential in both prophylactic and therapeutic applications, offering insights into their future development and role in cancer immunotherapy.

Cancer Nanovaccines: Nanomaterials and Clinical Perspectives

Cancer nanovaccines represent a promising frontier in cancer immunotherapy, utilizing nanotechnology to augment traditional vaccine efficacy. This review comprehensively examines the current state-of-the-art in cancer nanovaccine development, elucidating innovative strategies and technologies employed in their design. It explores both preclinical and clinical advancements, emphasizing key studies demonstrating their potential to elicit robust anti-tumor immune responses. The study encompasses various facets, including integrating biomaterial-based nanocarriers for antigen delivery, adjuvant selection, and the impact of nanoscale properties on vaccine performance. Detailed insights into the complex interplay between the tumor microenvironment and nanovaccine responses are provided, highlighting challenges and opportunities in optimizing therapeutic outcomes. Additionally, the study presents a thorough analysis of ongoing clinical trials, presenting a snapshot of the current clinical landscape. By curating the latest scientific findings and clinical developments, this study aims to serve as a comprehensive resource for researchers and clinicians engaged in advancing cancer immunotherapy. Integrating nanotechnology into vaccine design holds immense promise for revolutionizing cancer treatment paradigms, and this review provides a timely update on the evolving landscape of cancer nanovaccines.

Current status of nano-vaccinology in veterinary medicine science

Vaccination programmes provide a safe, effective and cost-efficient strategy for maintaining population health. In veterinary medicine, vaccination not only reduces disease within animal populations but also serves to enhance public health by targeting zoonoses. Nevertheless, for many pathogens, an effective vaccine remains elusive. Recently, nanovaccines have proved to be successful for various infectious and non-infectious diseases of animals. These novel technologies, such as virus-like particles, self-assembling proteins, polymeric nanoparticles, liposomes and virosomes, offer great potential for solving many of the vaccine production challenges. Their benefits include low immunotoxicity, antigen stability, enhanced immunogenicity, flexibility sustained release and the ability to evoke both humoral and cellular immune responses. Nanovaccines are more efficient than traditional vaccines due to ease of control and plasticity in their physio-chemical properties. They use a highly targeted immunological approach which can provide strong and long-lasting immunity. This article reviews the currently available nanovaccine technology and considers its utility for both infectious diseases and non-infectious diseases such as auto-immunity and cancer. Future research opportunities and application challenges from bench to clinical usage are also discussed.

Universal Fe/Mn Nanoadjuvant with T1/T2 MRI Self-Navigation and Gas Generation for Ideal Vaccines with Precise Tracking

Because of the distinguished properties between nanovaccine and traditional vaccine, the precise guidelines for nanovaccines with an optimal vaccination strategy to induce ideal immunities are greatly desired for combating major diseases, including cancer and infections. Herein, we designed and synthesized a self-navigating nanoadjuvant composed of Fe-doped manganese carbonate and its nanovaccine via a facile method. First, the degradation of the nanoadjuvant under acidic milieu of immune cells in lymph nodes would generate T1 and T2 MR imaging (MRI) signals to reflect the transformation dynamics of the nanovaccine and inform us when the next vaccination needed. Under this guideline, nanovaccines with a precise vaccination strategy triggered robust antigen-specific immune responses and immunological memory to effectively prevent ovalbumin (OVA)-expressing melanoma relapse by activating dendritic cells via a stimulator of interferon genes (STING) signaling pathway and inducing antigen cross-presentation by shaping lysosome integrity with CO2 generation and upregulating transporter associated antigen processing 1 (TAP-1) transporter. This study provides a universal nanoadjuvant with imaging self-guidance, immunopotentiating, and cross-priming activities for developing precise vaccines with an optimal immunization strategy to combat major diseases.

An antigen self-assembled and dendritic cell-targeted nanovaccine for enhanced immunity against cancer

The rise of nanotechnology has opened new horizons for cancer immunotherapy. However, most nanovaccines fabricated with nanomaterials suffer from carrier-related concerns, including low drug loading capacity, unpredictable metabolism, and potential systemic toxicity, which bring obstacles for their clinical translation. Herein, we developed an antigen self-assembled nanovaccine, which was resulted from a simple acryloyl modification of the antigen to induce self-assembly. Furthermore, a dendritic cell targeting head mannose monomer and a mevalonate pathway inhibitor zoledronic acid (Zol) were integrated or absorbed onto the nanoparticles (denoted as MEAO-Z) to intensify the immune response. The synthesized nanovaccine with a diameter of around 70 nm showed successful lymph node transportation, high dendritic cell internalization, promoted costimulatory molecule expression, and preferable antigen cross-presentation. In virtue of the above superiorities, MEAO-Z induced remarkably higher titers of serum antibody, stronger cytotoxic T lymphocyte immune responses and IFN-γ secretion than free antigen and adjuvants. In vivo, MEAO-Z significantly suppressed EG7-OVA tumor growth and prolonged the survival time of tumor-bearing mice. These results indicated the translation promise of our self-assembled nanovaccine for immune potentiation and cancer immunotherapy.

Adjuvant physiochemistry and advanced nanotechnology for vaccine development

Vaccines comprising innovative adjuvants are rapidly reaching advanced translational stages, such as the authorized nanotechnology adjuvants in mRNA vaccines against COVID-19 worldwide, offering new strategies to effectively combat diseases threatening human health. Adjuvants are vital ingredients in vaccines, which can augment the degree, extensiveness, and longevity of antigen specific immune response. The advances in the modulation of physicochemical properties of nanoplatforms elevate the capability of adjuvants in initiating the innate immune system and adaptive immunity, offering immense potential for developing vaccines against hard-to-target infectious diseases and cancer. In this review, we provide an essential introduction of the basic principles of prophylactic and therapeutic vaccination, key roles of adjuvants in augmenting and shaping immunity to achieve desired outcomes and effectiveness, and the physiochemical properties and action mechanisms of clinically approved adjuvants for humans. We particularly focus on the preclinical and clinical progress of highly immunogenic emerging nanotechnology adjuvants formulated in vaccines for cancer treatment or infectious disease prevention. We deliberate on how the immune system can sense and respond to the physicochemical cues (e.g., chirality, deformability, solubility, topology, and chemical structures) of nanotechnology adjuvants incorporated in the vaccines. Finally, we propose possible strategies to accelerate the clinical implementation of nanotechnology adjuvanted vaccines, such as in-depth elucidation of nano-immuno interactions, antigen identification and optimization by the deployment of high-dimensional multiomics analysis approaches, encouraging close collaborations among scientists from different scientific disciplines and aggressive exploration of novel nanotechnologies.

Macro-microporous ZIF-8 MOF complexed with lysosomal pH-adjusting hexadecylsulfonylfluoride as tumor vaccine delivery systems for improving anti-tumor cellular immunity

Tumor vaccine therapy, which can induce tumor antigen-specific cellular immune responses to directly kill tumor cells, is considered to be one of the most promising tumor immunotherapies. How to elicit effective tumor antigen-specific cellular immunity is the key for the development of tumor vaccines. However, current tumor vaccines with conventional antigen delivery systems mainly induce humoral immunity but not effective cellular immunity. In this study, based on pH-sensitive, ordered macro-microporous zeolitic imidazolate framework-8 (SOM-ZIF-8) and hexadecylsulfonylfluoride (HDSF), an intelligent tumor vaccine delivery system SOM-ZIF-8/HDSF was developed to elicit potent cellular immunity. Results demonstrated that the SOM-ZIF-8 particles could efficiently encapsulate antigen into the macropores, promote antigen uptake by antigen-presenting cells, facilitate lysosomal escape, and enhance antigen cross-presentation and cellular immunity. In addition, the introduction of HDSF could up-regulate the lysosomal pH to protect antigens from acid degradation, which further promoted antigen cross-presentation and cellular immunity. The immunization tests showed that the tumor vaccines based on the delivery system improved antigen-specific cellular immune response. Moreover, the tumor vaccines significantly inhibited tumor growth in B16 melanoma-bearing C57BL/6 mice. These results indicate that SOM-ZIF-8/HDSF as an intelligent vaccine delivery system could be used for the development of novel tumor vaccines.

Biopolymer-Based Nanogel Approach in Drug Delivery: Basic Concept and Current Developments

Due to their increased surface area, extent of swelling and active substance-loading capacity and flexibility, nanogels made from natural and synthetic polymers have gained significant interest in scientific and industrial areas. In particular, the customized design and implementation of nontoxic, biocompatible, and biodegradable micro/nano carriers makes their usage very feasible for a range of biomedical applications, including drug delivery, tissue engineering, and bioimaging. The design and application methodologies of nanogels are outlined in this review. Additionally, the most recent advancements in nanogel biomedical applications are discussed, with particular emphasis on applications for the delivery of drugs and biomolecules.

Biomaterials Facilitating Dendritic Cell-Mediated Cancer Immunotherapy

Dendritic cell (DC)-based cancer immunotherapy has exhibited remarkable clinical prospects because DCs play a central role in initiating and regulating adaptive immune responses. However, the application of traditional DC-mediated immunotherapy is limited due to insufficient antigen delivery, inadequate antigen presentation, and high levels of immunosuppression. To address these challenges, engineered biomaterials have been exploited to enhance DC-mediated immunotherapeutic effects. In this review, vital principal components that can enhance DC-mediated immunotherapeutic effects are first introduced. The parameters considered in the rational design of biomaterials, including targeting modifications, size, shape, surface, and mechanical properties, which can affect biomaterial optimization of DC functions, are further summarized. Moreover, recent applications of various engineered biomaterials in the field of DC-mediated immunotherapy are reviewed, including those serve as immune component delivery platforms, remodel the tumor microenvironment, and synergistically enhance the effects of other antitumor therapies. Overall, the present review comprehensively and systematically summarizes biomaterials related to the promotion of DC functions; and specifically focuses on the recent advances in biomaterial designs for DC activation to eradicate tumors. The challenges and opportunities of treatment strategies designed to amplify DCs via the application of biomaterials are discussed with the aim of inspiring the clinical translation of future DC-mediated cancer immunotherapies.

Utilization of Stimuli-Responsive Biomaterials in the Formulation of Cancer Vaccines

Immunology research has focused on developing cancer vaccines to increase the number of tumor-specific effector cells and their ability to fight cancer over the last few decades. There is a lack of professional success in vaccines compared to checkpoint blockade and adoptive T-cell treatment. The vaccine's inadequate delivery method and antigen selection are most likely to blame for the poor results. Antigen-specific vaccines have recently shown promising results in preclinical and early clinical investigations. To target particular cells and trigger the best immune response possible against malignancies, it is necessary to design a highly efficient and secure delivery method for cancer vaccines; however, enormous challenges must be overcome. Current research is focused on developing stimulus-responsive biomaterials, which are a subset of the range of levels of materials, to enhance therapeutic efficacy and safety and better regulate the transport and distribution of cancer immunotherapy in vivo. A concise analysis of current developments in the area of biomaterials that respond to stimuli has been provided in brief research. Current and anticipated future challenges and opportunities in the sector are also highlighted.

CaCO3 powder-mediated biomineralization of antigen nanosponges synergize with PD-1 blockade to potentiate anti-tumor immunity

Antigen self-assembly nanovaccines advance the minimalist design of therapeutic cancer vaccines, but the issue of inefficient cross-presentation has not yet been fully addressed. Herein, we report a unique approach by combining the concepts of "antigen multi-copy display" and "calcium carbonate (CaCO₃) biomineralization" to increase cross-presentation. Based on this strategy, we successfully construct sub-100 nm biomineralized antigen nanosponges (BANSs) with high CaCO₃ loading (38.13 wt%) and antigen density (61.87%). BANSs can be effectively uptaken by immature antigen-presenting cells (APCs) in the lymph node upon subcutaneous injection. Achieving efficient spatiotemporal coordination of antigen cross-presentation and immune effects, BANSs induce the production of CD4⁺ T helper cells and cytotoxic T lymphocytes, resulting in effective tumor growth inhibition. BANSs combined with anti-PD-1 antibodies synergistically enhance anti-tumor immunity and reverse the tumor immunosuppressive microenvironment. Overall, this CaCO₃ powder-mediated biomineralization of antigen nanosponges offer a robust and safe strategy for cancer immunotherapy.

In Situ Separable Nanovaccines with Stealthy Bioadhesive Capability for Durable Cancer Immunotherapy

Because of tumor heterogeneity and the immunosuppressive tumor microenvironment, most cancer vaccines typically do not elicit robust antitumor immunological responses in clinical trials. In this paper, we report findings about a bioadhesive nanoparticle (BNP)-based separable cancer vaccine, FeSHK@B-ovalbumin (OVA), to target multi-epitope antigens and exert effective cancer immunotherapy. After the FeSHK@B-OVA "nanorocket" initiates the "satellite-rocket separation" procedure in the acidic tumor microenvironment, the FeSHK@B "launch vehicle" can amplify intracellular oxidative stress persistently. This procedure allows for bioadhesiveness-mediated prolonged drug retention within the tumor tissue and triggers the immunogenic death of tumor cells that transforms the primary tumors into antigen depots, which acts synergistically with the OVA "satellite" to trigger robust antigen-specific antitumor immunity. The cooperation of these two immunostimulants not only efficiently inhibits the primary tumor growth and provokes durable antigen-specific immune activation in vivo but also activates a long-term and robust immune memory effect to resist tumor rechallenge and metastasis. These results highlight the enormous potential of FeSHK@B-OVA to serve as an excellent therapeutic and prophylactic cancer nanovaccine. By leveraging the antigen depots in situ and the synergistic effect among multi-epitope antigens, such a nanovaccine strategy with stealthy bioadhesion may offer a straightforward and efficient approach to developing various cancer vaccines for different types of tumors.

Vaccine-like nanomedicine for cancer immunotherapy

The successful clinical application of immune checkpoint blockade (ICB) and chimeric antigen receptor T cells (CAR-T) therapeutics has attracted extensive attention to immunotherapy, however, their drawbacks such as limited specificity, persistence and toxicity haven't met the high expectations on efficient cancer treatments. Therapeutic cancer vaccines which instruct the immune system to capture tumor specific antigens, generate long-term immune memory and specifically eliminate cancer cells gradually become the most promising strategies to eradicate tumor. However, the disadvantages of some existing vaccines such as weak immunogenicity and in vivo instability have restricted their development. Nanotechnology has been recently incorporated into vaccine fabrication and exhibited promising results for cancer immunotherapy. Nanoparticles promote the stability of vaccines, as well as enhance antigen recognition and presentation owing to their nanometer size which promotes internalization of antigens by phagocytic cells. The surface modification with targeting units further permits the delivery of vaccines to specific cells. Meanwhile, nanocarriers with adjuvant effect can improve the efficacy of vaccines. In addition to classic vaccines composed of antigens and adjuvants, the nanoparticle-mediated chemotherapy, radiotherapy and certain other therapeutics could induce the release of tumor antigens in situ, which therefore effectively simulate antitumor immune responses. Such vaccine-like nanomedicine not only kills primary tumors, but also prevents tumor recurrence and helps eliminate metastatic tumors. Herein, we introduce recent developments in nanoparticle-based delivery systems for antigen delivery and in situ antitumor vaccination. We will also discuss the remaining opportunities and challenges of nanovaccine in clinical translation towards cancer treatment.

Tumor-Antigen Activated Dendritic Cell Membrane-Coated Biomimetic Nanoparticles with Orchestrating Immune Responses Promote Therapeutic Efficacy against Glioma

Immunotherapy has had a profound positive effect on certain types of cancer but has not improved the outcomes of glioma because of the blood-brain barrier (BBB) and immunosuppressive tumor microenvironment. In this study, we developed an activated mature dendritic cell membrane (aDCM)-coated nanoplatform, rapamycin (RAPA)-loaded poly(lactic-co-glycolic acid) (PLGA), named aDCM@PLGA/RAPA, which is a simple, efficient, and individualized strategy to cross the BBB and improve the immune microenvironment precisely. In vitro cells uptake and the transwell BBB model revealed that the aDCM@PLGA/RAPA can enhance homotypic-targeting and BBB-crossing efficiently. According to the in vitro and in vivo immune response efficacy of aDCM@PLGA/RAPA, the immature dendritic cells (DCs) could be stimulated into the matured status, which leads to further activation of immune cells, such as tumor-infiltrating T cells and natural killer cells, and can induce the subsequent immune responses through direct and indirect way. The aDCM@PLGA/RAPA treatment can not only inhibit glioma growth significantly but also has favorable potential ability to induce glial differentiation in the orthotopic glioma. Moreover, the aDCM@PLGA could induce a robust CD8⁺ effector and therefore suppress orthotopic glioma growth in a prophylactic setup, which indicates certain tumor immunity. Overall, our work provides an effective antiglioma drug delivery system which has great potential for tumor combination immunotherapy.

Boosting cancer immunotherapy by biomineralized nanovaccine with ferroptosis-inducing and photothermal properties

Until now, treatment of refractory tumors and uncontrolled metastasis by cancer immunotherapy has not yet achieved satisfactory therapeutic results due to the insufficient in vivo immune response. Here, we proposed the construction of a therapeutic cancer nanovaccine Fe@OVA-IR820 with ferroptosis-inducing and photothermal properties for boosting cancer immunotherapy. Fe³⁺ ions were chelated inside the exogenous antigen ovalbumin (OVA) by biomineralization to form the nanovaccine, to which the photosensitizer IR820 was loaded by electrostatic incorporation. After intratumoral injection, in situ immunogenic cell death (ICD) was triggered as a result of Fe³⁺-dependent ferroptosis. Endogenous neoantigens and damage-associated molecular patterns (DAMPs) were released because of ICD and worked synergically with the exogenous OVA to provoke the immune response, which was further amplified by the photothermal effect after near-infrared irradiation. The enhanced recruitment and infiltration of T cells were observed and resulted in the suppression of the primary tumor. The therapeutic regiment that combined Fe@OVA-IR820 nanovaccine with cytotoxic T lymphocyte-associated protein 4 (CTLA-4) checkpoint blockade significantly boosted anti-cancer immunity and inhibited the growth of distal simulated metastases. Therefore, we proposed Fe@OVA-IR820 nanovaccine combined checkpoint blockade as a potential therapeutic strategy for melanoma treatment.

Dendritic cell derived exosomes loaded neoantigens for personalized cancer immunotherapies

Despite the promising potential of cancer vaccine, their efficacy has been limited in clinical trials and improved methods are urgently needed. Here we designed a nanovaccine platform that contains dendritic cell derived exosomes carriers and patient-specific neoantigens for individualized immunotherapies. The nanovaccine exhibited convenient cargo loading and prolonged cargo transportation to the lymph nodes, followed by eliciting potent antigen specific broad-spectrum T-cell and B-cell-mediated immune responses with great biosafety and biocompatibility. Strikingly, delivery of neoantigen-exosome nanovaccine significantly prohibited tumor growth, prolonged survival, delayed tumor occurrences with long-term memory, eliminated the lung metastasis in the therapeutic, prophylactic and metastatic B16F10 melanoma as well as therapeutic MC-38 models, respectively. Additionally, exosome-based nanovaccine demonstrated synergistic antitumor response superior to liposomal formulation due to presence of exosomal proteins. Collectively, our research indicated improved strategies for cell free vaccines and suggested exosome-based nanoplatform for cancer immunotherapy and personalized nanotechnology. These findings represent a powerful pathway to generate individualized nanovaccine rapidly for clinical application.

Phenylboronic ester-modified polymeric nanoparticles for promoting TRP2 peptide antigen delivery in cancer immunotherapy

The tremendous development of peptide-based cancer vaccine has attracted incremental interest as a powerful approach in cancer management, prevention and treatment. As successful as tumor vaccine has been, major challenges associated with achieving efficient immune response against cancer are (1) drainage to and retention in lymph nodes; (2) uptake by dendritic cells (DCs); (3) activation of DCs. In order to overcome these barriers, here we construct PBE-modified TRP2 nanovaccine, which comprises TRP2 peptide tumor antigen and diblock copolymer PEG-b-PAsp grafted with phenylboronic ester (PBE). We confirmed that this TRP2 nanovaccine can be effectively trapped into lymph node, uptake by dendritic cells and induce DC maturation, relying on increased negative charge, ROS response and pH response. Consistently, this vehicle loaded with TRP2 peptide could boost the strongest T cell immune response against melanoma in vivo and potentiate antitumor efficacy both in tumor prevention and tumor treatment without any exogenous adjuvant. Furthermore, the TRP2 nanovaccine can suppress the tumor growth and prolong animal survival time, which may result from its synergistic effect of inhibiting tumor immunosuppression and increasing cytotoxic lymphocyte (CTL) response. Hence this type of PBE-modified nanovaccine would be widely used as a simple, safe and robust platform to deliver other antigen in cancer immunotherapy.

Modified hollow mesoporous silica nanoparticles as immune adjuvant-nanocarriers for photodynamically enhanced cancer immunotherapy

Nanomedicine has demonstrated great potential in enhancing cancer immunotherapy. However, nanoparticle (NP)-based immunotherapy still has limitations in inducing effective antitumor responses and inhibiting tumor metastasis. Herein, polyethylenimine (PEI) hybrid thin shell hollow mesoporous silica NPs (THMSNs) were applied as adjuvant-nanocarriers and encapsulated with very small dose of photosensitizer chlorine e6 (Ce6) to realize the synergy of photodynamic therapy (PDT)/immunotherapy. Through PEI etching, the obtained Ce6@THMSNs exhibited enhanced cellular internalization and endosome/lysosome escape, which further improved the PDT efficacy of Ce6@THMSNs in destroying tumor cells. After PDT treatment, the released tumor-associated antigens with the help of THMSNs as adjuvants promoted dendritic cells maturation, which further boosted CD8⁺ cytotoxic T lymphocytes activation and triggered antitumor immune responses. The in vivo experiments demonstrated the significant potency of Ce6@THMSNs-based PDT in obliterating primary tumors and inducing persistent tumor-specific immune responses, thus preventing distant metastasis. Therefore, we offer a THMSNs-mediated and PDT-triggered nanotherapeutic system with immunogenic property, which can elicit robust antitumor immunity and is promising for future clinical development of immunotherapy.

Nucleic acid and oligonucleotide delivery for activating innate immunity in cancer immunotherapy

A group of nucleic acids and oligonucleotides play various roles in the innate immune system. They can stimulate pattern recognition receptors to activate innate immune cells, encode immunostimulatory proteins or peptides, or silence specific genes to block negative regulators of immune cells. Given the limitations of current cancer immunotherapy, there has been increasing interest in harnessing innate immune responses by nucleic acids and oligonucleotides. The poor biopharmaceutical properties of nucleic acids and oligonucleotides make it critical to use carriers that can protect them in circulation, retain them in the tumor microenvironment, and bring them to intracellular targets. Therefore, various gene carriers have been repurposed to deliver nucleic acids and oligonucleotides for cancer immunotherapy and improve their safety and activity. Here, we review recent studies that employed carriers to enhance the functions of nucleic acids and oligonucleotides and overall immune responses to cancer, and discuss remaining challenges and future opportunities in the development of nucleic acid-based immunotherapeutics.

Nano dimensions/adjuvants in COVID-19 vaccines

A favorable outcome of the COVID-19 crisis might be achieved with massive vaccination. The proposed vaccines contain several different vaccine active principles (VAP), such as inactivated virus, antigen, mRNA, and DNA, which are associated with either standard adjuvants or nanomaterials (NM) such as liposomes in Moderna's and BioNTech/Pfizer's vaccines. COVID-19 vaccine adjuvants may be chosen among liposomes or other types of NM composed for example of graphene oxide, carbon nanotubes, micelles, exosomes, membrane vesicles, polymers, or metallic NM, taking inspiration from cancer nano-vaccines, whose adjuvants may share some of their properties with those of viral vaccines. The mechanisms of action of nano-adjuvants are based on the facilitation by NM of targeting certain regions of immune interest such as the mucus, lymph nodes, and zones of infection or blood irrigation, the possible modulation of the type of attachment of the VAP to NM, in particular VAP positioning on the NM external surface to favor VAP presentation to antigen presenting cells (APC) or VAP encapsulation within NM to prevent VAP degradation, and the possibility to adjust the nature of the immune response by tuning the physico-chemical properties of NM such as their size, surface charge, or composition. The use of NM as adjuvants or the presence of nano-dimensions in COVID-19 vaccines does not only have the potential to improve the vaccine benefit/risk ratio, but also to reduce the dose of vaccine necessary to reach full efficacy. It could therefore ease the overall spread of COVID-19 vaccines within a sufficiently large portion of the world population to exit the current crisis.

Nanotechnology-Based Approaches to Promote Lymph Node Targeted Delivery of Cancer Vaccines

Vaccines are a promising immunotherapy that awakens the human immune system to inhibit and eliminate cancer with fewer side effects compared with traditional radiotherapy and chemotherapy. Although cancer vaccines have shown some efficacy, there are still troublesome bottlenecks to expand their benefits in the clinic, including weak immune effects and limited therapeutic outcomes. In the past few years, in addition to neoantigen screening, a main branch of the efforts has been devoted to promoting the lymph nodes (LNs) targeting of cancer vaccines and the cross-presentation of antigens by dendritic cells (DCs), two cardinal stages in effective initiation of the immune response. Especially, nanomaterials have shown hopeful biomedical applications in the improvement of vaccine effectiveness. This Review briefly outlines the possible mechanisms by which nanoparticle properties affect LN targeting and antigen cross-presentation and then gives an overview of state-of-the-art advances in improving these biological outcomes with nanotechnology.

Reduction-Sensitive Protein Nanogels Enhance Uptake of Model and Tumor Lysate Antigens In Vitro by Mouse- and Human-Derived Dendritic Cells

Peptides and proteins represent an emerging class of powerful therapeutics. Peptide and protein nanogels are attractive carriers for the transport and delivery of biologically active peptides and proteins because they allow essentially quantitative encapsulation of these biologics. One interesting field of use of peptide and protein nanogels is the transport of antigens and adjuvants in cancer immunotherapy. This study demonstrates the use of reduction-sensitive protein nanogels for the delivery of ovalbumin and oxidized tumor lysate-based antigens to mouse and human-donor-derived dendritic cells. Challenging mouse-derived and human dendritic cells with reduction-sensitive ovalbumin nanogels was found to significantly enhance antigen uptake as compared to the use of the corresponding free protein antigen. The experiments with mouse-derived dendritic cells further showed that the administration of ovalbumin in the form of reduction-sensitive nanogels enhanced dendritic cell maturation as well as the presentation of the SIINFEKL epitope as compared to experiments that use free ovalbumin. In addition to ovalbumin as a model antigen, the feasibility of reduction-sensitive nanogels was also demonstrated for the delivery of oxidized, whole tumor lysate-based cancer antigens. In experiments with dendritic cells harvested from human donors, dendritic cell uptake of the oxidized tumor lysate antigen was significantly enhanced in experiments that used oxidized tumor lysate nanogels as compared to the free antigen.

Hybrid Vesicles Based on Autologous Tumor Cell Membrane and Bacterial Outer Membrane To Enhance Innate Immune Response and Personalized Tumor Immunotherapy

Tumor heterogeneity, often leading to metastasis, limits the development of tumor therapy. Personalized therapy is promising to address tumor heterogeneity. Here, a vesicle system was designed to enhance innate immune response and amplify personalized immunotherapy. Briefly, the bacterial outer membrane vesicle (OMV) was hybridized with the cell membrane originated from the tumor (mT) to form new functional vesicles (mTOMV). In vitro experiments revealed that the mTOMV strengthened the activation of innate immune cells and increased the specific lysis ability of T cells in homogeneous tumors. In vivo experiments showed that the mTOMV effectively accumulated in inguinal lymph nodes, then inhibited lung metastasis. Besides, the mTOMV evoked adaptive immune response in homologous tumor rather than the heterogeneous tumor, reversibly demonstrating the effects of personalized immunotherapy. The functions to inhibit tumor growth and metastasis accompanying good biocompatibility and simple preparation procedure of mTOMV provide their great potential for clinical applications.

Hydrogel/nanoadjuvant-mediated combined cell vaccines for cancer immunotherapy

Combined cell vaccines of tumor whole cells and dendritic cells (DCs) provide an effective individualized immunotherapy for malignant tumors. We propose an innovative strategy termed "biomaterial-mediated combined cell vaccines for immunotherapy," which combines tumor cell and DC vaccines with a cyclodextrin-polyethylene glycol hydrogel and a cytosine-phosphate-guanine (CpG) nanoadjuvant. The nanoadjuvant promotes antigen presentation and amplifies immune-eliciting potency by co-delivery of antigens and adjuvants. The hydrogel scaffold provides a better growth microenvironment for injected exogenous DCs and recruits endogenous DCs to maintain their viability for synergistic effect. The results indicated that, relative to live tumor cells, the immunogenically dying tumor cells activated DC maturation effectively with the auxiliary effect of immune adjuvant CpG nanoparticles. The increased T cell percentage, proliferation ability, cytokine secretion, and cytotoxic effect revealed the enhanced immunogenicity of the combined cell vaccines. The combined hydrogel/nanoadjuvant system showed the best efficiency in inhibiting tumor growth. Moreover, vaccination with a single dose of hydrogel-based combined vaccines significantly delayed the development of tumors. The biomaterial-mediated combined cell vaccines remarkably increased the infiltration of effector T cells, alleviated the intratumoral immunosuppressive microenvironment, and maximized the immune effect of the vaccines, thus improving cancer immunotherapy. STATEMENT OF SIGNIFICANCE: Cell-based vaccines, including tumor whole-cell vaccine or DC vaccine, have attracted wide attention as an effective method for cancer immunotherapy. However, it is difficult to gain satisfactory outcomes in clinical trials because of the low immunogenicity of tumor whole cell vaccine and the short-term survival of transferred DC vaccine. Therefore, improving the ability of cell-based vaccines to induce a strong and durable immune response is the primary objective for vaccine development. Biomaterial-mediated combined cell vaccines is an innovative strategy for cancer immunotherapy. The combined hydrogel/ nanoadjuvant system comprises immunogenically dying tumor cells, DCs, and nanoadjuvants. Nanoadjuvant-loaded immunogenically dying tumor cells can induce efficient immune response as the tumor cell vaccine. The hydrogel-based combined tumor cell/DC vaccine could be used for individualized immunotherapy.

Nanovaccine biomineralization for cancer immunotherapy: a NADPH oxidase-inspired strategy for improving antigen cross-presentation via lipid peroxidation

Current efforts to develop novel vaccine nanotechnologies to increase cytotoxic T lymphocytes have met the challenges of the limited efficacy of antigen cross-presentation. Recent studies have uncovered a unique biological mechanism by which activation of the NADPH oxidase 2 (NOX2) complex, a major source of reactive oxygen species (ROS), enhances the cross-presentation by antigen-presenting cells (APCs). Inspired by the NOX2 mechanism, we devise biomineralized nanovaccines named NVs^cp, which are developed by in situ growth of calcium peroxide on nanovaccines self-assembled with the model antigen ovalbumin. The ~80 nm NVs^cp efficiently flow to the draining lymph nodes, where they accumulate within APC endo-/lysosomes, and generate a rapid burst of ROS in response to the acidic endo-/lysosomal environment with the subsequent endo-/lysosomal lipid peroxidation. Accompanied by the process, NVs^cp stimulate distinct APCs maturation and antigen presentation to T lymphocytes. Notably, high levels of antigen-specific CD8⁺ T cell responses, accompanied by the induction of CD4⁺ T helper cells, are achieved. More importantly, NVs^cp significantly increase the ratios of intratumoral CD8⁺ T/regulatory T cells and achieve prominent tumor therapy effects. The NOX2-inspired biomineralized NVs^cp represent an effective and easily applicable strategy that enables the strong cross-presentation of exogenous vaccine antigens.

CpG-Based Nanovaccines for Cancer Immunotherapy

Cancer has been a serious health hazard to the people all over the world with its high incidence and horrible mortality. In recent years, tumor vaccines in immunotherapy have become a hotspot in cancer therapy due to their many practical advantages and good therapeutic potentials. Among the various vaccines, nanovaccine utilized nanoparticles (NPs) as the carrier and/or adjuvant has presented significant therapeutic effect in cancer treatment. For tumor nanovaccines, unmethylated cytosine-phosphate-guanine oligodeoxynucleotide (CpG ODN) is a commonly used adjuvant. It has been reported that CpG ODN was the most effective immune stimulant among the currently known adjuvants. It could be recognized by toll-like receptor 9 (TLR9) to activate humoral and cellular immunity for preventing or treating cancer. In this review, the topic of CpG-based nanovaccines for cancer immunotherapy will be focused. The types and properties of different CpG will be introduced in detail first, and then some representative tumor nanovaccines will be reviewed according to the diverse loading modes of CpG, such as electrostatic adsorption, covalent bonding, hydrophilic and hydrophobic interaction, and DNA self-assembly, for summarizing the current progress of CpG-based tumor nanovaccines. Finally, the challenges and future perspectives will be discussed. It is hoped that this review will provide valuable references for the development of nanovaccines in cancer immunotherapy.

Hybrid Membrane-Coated Biomimetic Nanoparticles (HM@BNPs): A Multifunctional Nanomaterial for Biomedical Applications

The application of nanoparticles in the diagnosis and treatment of diseases has undergone different developmental stages, but phagocytosis and nonspecific distribution have been the main factors restricting the transformation of nanobased drugs into clinical practice. In the past decade, the design of membrane-coated nanoparticles has gained increasing attention. It is hoped that the combination of the cell membrane's natural biological properties and the functional integration of synthetic nanoparticle systems can compensate for the shortage of traditional nanoparticles. The membrane coating gives the nanoparticles unique biological functions such as immune evasion and targeting capability. However, when the encapsulation of monotypic membranes does not meet the diverse demands of biomedicine, the combination of different cell membranes may offer more possibilities. In this review, the composition, preparation, and advantages of biomimetic nanoparticles coated with hybrid cell membranes are summarized, and the applications of hybrid membrane-coated biomimetic nanoparticles (HM@BNPs) in drug delivery, phototherapy, liquid biopsy, tumor vaccines, immune therapy, and detoxification are reviewed. Finally, the current challenges and opportunities with regard to HM@BNPs are discussed.

Harnessing Innate Immunity Using Biomaterials for Cancer Immunotherapy

The discovery of immune checkpoint blockade has revolutionized the field of immuno-oncology and established the foundation for developing various new therapies that can surpass conventional cancer treatments. Most recent immunotherapeutic strategies have focused on adaptive immune responses by targeting T cell-activating pathways, genetic engineering of T cells with chimeric antigen receptors, or bispecific antibodies. Despite the unprecedented clinical success, these T cell-based treatments have only benefited a small proportion of patients. Thus, the need for the next generation of cancer immunotherapy is driven by identifying novel therapeutic molecules or new immunoengineered cells. To maximize the therapeutic potency via innate immunogenicity, the convergence of innate immunity-based therapy and biomaterials is required to yield an efficient index in clinical trials. This review highlights how biomaterials can efficiently reprogram and recruit innate immune cells in tumors and ultimately initiate activation of T cell immunity against advanced cancers. Moreover, the design and specific biomaterials that improve innate immune cells' targeting ability to selectively activate immunogenicity with minimal adverse effects are discussed.

Nanovaccine-Based Strategies to Overcome Challenges in the Whole Vaccination Cascade for Tumor Immunotherapy

Nanovaccine-based immunotherapy (NBI) has received greater attention recently for its potential to prime tumor-specific immunity and establish a long-term immune memory that prevents tumor recurrence. Despite encouraging results in the recent studies, there are still numerous challenges to be tackled for eliciting potent antitumor immunity using NBI strategies. Based on the principles that govern immune response, here it is proposed that these challenges need to be addressed at the five critical cascading events: Loading tumor-specific antigens by nanoscale drug delivery systems (L); Draining tumor antigens to lymph nodes (D); Internalization by dendritic cells (DCs) (I); Maturation of DCs by costimulatory signaling (M); and Presenting tumor-peptide-major histocompatibility complexes to T cells (P) (LDIMP cascade in short). This review provides a detailed and objective overview of emerging NBI strategies to improve the efficacy of nanovaccines in each step of the LDIMP cascade. It is concluded that the balance between each step must be optimized by delicate designing and modification of nanovaccines and by combining with complementary approaches to provide a synergistic immunity in the fight against cancer.

Protein-Based Nanomedicine for Therapeutic Benefits of Cancer

Proteins, a type of natural biopolymer that possess many prominent merits, have been widely utilized to engineer nanomedicine for fighting against cancer. Motivated by their ever-increasing attention in the scientific community, this review aims to provide a comprehensive showcase on the current landscape of protein-based nanomedicine for cancer therapy. On the basis of role differences of proteins in nanomedicine, protein-based nanomedicine engineered with protein therapeutics, protein carriers, enzymes, and composite proteins is introduced. The cancer therapeutic benefits of the protein-based nanomedicine are also discussed, including small-molecular therapeutics-mediated therapy, macromolecular therapeutics-mediated therapy, radiation-mediated therapy, reactive oxygen species-mediated therapy, and thermal effect-mediated therapy. Lastly, future developments and potential challenges of protein-based nanomedicine are elucidated toward clinical translation. It is believed that protein-based nanomedicine will play a vital role in the battle against cancer. We hope that this review will inspire extensive research interests from diverse disciplines to further push the developments of protein-based nanomedicine in the biomedical frontier, contributing to ever-greater medical advances.

An MRI-trackable therapeutic nanovaccine preventing cancer liver metastasis

Cancer vaccines consisting of tumor-associated antigens (TAAs) can initiate a powerful antitumor immune response through antigen-presenting cells, such as dendritic cells (DCs) and macrophages, and have shown great potential in cancer prevention and therapy. However, poor anticancer efficacy and an uncertain immunization process have hitherto limited the application of cancer vaccines. Herein, a multifunctional nanovaccine comprising ovalbumin (OVA), MnO₂, and polydopamine (OMPN) was prepared by a facile one-pot method. OMPN displayed excellent anticancer efficacy against an orthotopic melanoma and could also prevent liver metastasis in a tumor re-challenge mice model. Additionally, the migration behavior of DCs in the inguinal lymph node after vaccination was tracked by MRI contrasted with OMPN, indicating successful DC activation and immune response. The superior anticancer efficacy, especially the high efficiency against tumor metastasis, and the capability of tracking the immunization process make OMPN a very promising multifunctional nanovaccine for cancer therapy.

Recent Advancements in Nanomedicine for 'Cold' Tumor Immunotherapy

Although current anticancer immunotherapies using immune checkpoint inhibitors (ICIs) have been reported with a high clinical success rate, numerous patients still bear 'cold' tumors with insufficient T cell infiltration and low immunogenicity, responding poorly to ICI therapy. Considering the advancements in precision medicine, in-depth mechanism studies on the tumor immune microenvironment (TIME) among cold tumors are required to improve the treatment for these patients. Nanomedicine has emerged as a promising drug delivery system in anticancer immunotherapy, activates immune function, modulates the TIME, and has been applied in combination with other anticancer therapeutic strategies. This review initially summarizes the mechanisms underlying immunosuppressive TIME in cold tumors and addresses the recent advancements in nanotechnology for cold TIME reversal-based therapies, as well as a brief talk about the feasibility of clinical translation.

Nanoparticle Delivery Systems with Cell-Specific Targeting for Pulmonary Diseases

Respiratory disorders are among the most important medical problems threatening human life. The conventional therapeutics for respiratory disorders are hindered by insufficient drug concentrations at pathological lesions, lack of cell-specific targeting, and various biobarriers in the conducting airways and alveoli. To address these critical issues, various nanoparticle delivery systems have been developed to serve as carriers of specific drugs, DNA expression vectors, and RNAs. The unique properties of nanoparticles, including controlled size and distribution, surface functional groups, high payload capacity, and drug release triggering capabilities, are tailored to specific requirements in drug/gene delivery to overcome major delivery barriers in pulmonary diseases. To avoid off-target effects and improve therapeutic efficacy, nanoparticles with high cell-targeting specificity are essential for successful nanoparticle therapies. Furthermore, low toxicity and high degradability of the nanoparticles are among the most important requirements in the nanoparticle designs. In this review, we provide the most up-to-date research and clinical outcomes in nanoparticle therapies for pulmonary diseases. We also address the current critical issues in key areas of pulmonary cell targeting, biosafety and compatibility, and molecular mechanisms for selective cellular uptake.

A vaccine for photodynamic immunogenic cell death: tumor cell caged by cellular disulfide-thiol exchange for immunotherapy

It has been suggested that immunogenic cell death (ICD) has therapeutic potential; however, its anticancer immunity is considerably hampered by the in situ immunosuppressive microenvironment within the tumor area, such as the dysfunction of antigen-presenting cells. Herein, we present an in vitro ICD-inducing modality to circumvent such impairment of immune activation. To this end, a "hot", i.e., immunogenic, whole tumor cell vaccine is generated in vitro and subcutaneously vaccinated in the normal tissue, departing from the site of the in situ immunosuppressive tumor area, to fully leverage the ICD-inducing antitumor immunity. In particular, the immunogenic dying tumor cells, caged by cellular disulfide-thiol exchange, are mediated by photoactivation. After subcutaneous vaccination, the photoactivated caged live cell vaccine (CLCV) exerts multi-durable immunostimulatory property, which, when adjuvanted by CpG, efficiently promotes dendritic cell (DC) activation and elicits robust CD8+ T-cell responses in vivo. Importantly, the generated T-cell responses are shown to protect 75% mice preimmunized with CLCV against tumor initiation and significantly retards tumor growth in the therapeutic setting. The strategy presented here may help to enrich the current vaccine design for cancer immunotherapy.

Bioengineering of nano metal-organic frameworks for cancer immunotherapy

Immunotherapy techniques, such as immune checkpoint inhibitors, chimeric antigen receptor (CAR) T cell therapies and cancer vaccines, have been burgeoning with great success, particularly for specific cancer types. However, side effects with fatal risks, dysfunction in tumor microenvironment and low immune response rates remain the bottlenecks in immunotherapy. Nano metal-organic frameworks (nMOFs), with an accurate structure and a narrow size distribution, are emerging as a solution to these problems. In addition to their function of temporospatial delivery, a large library of their compositions, together with flexibility in chemical interaction and inherent immune efficacy, offers opportunities for various designs of nMOFs for immunotherapy. In this review, we overview state-of-the-art research on nMOFs-based immunotherapies as well as their combination with other therapies. We demonstrate that nMOFs are predominantly customized for vaccine delivery or tumor-microenvironment modulation. Finally, a prospect of nMOFs in cancer immunotherapy will be discussed.

Therapeutic Vaccines for Cancer Immunotherapy

The rapid development of nanobiotechnology has enabled progress in therapeutic cancer vaccines. These vaccines stimulate the host innate immune response by tumor antigens followed by a cascading adaptive response against cancer. However, an improved antitumor immune response is still in high demand because of the unsatisfactory clinical performance of the vaccine in tumor inhibition and regression. To date, a complicated tumor immunosuppressive environment and suboptimal design are the main obstacles for therapeutic cancer vaccines. The optimization of tumor antigens, vaccine delivery pathways, and proper adjuvants for innate immune response initiation, along with reprogramming of the tumor immunosuppressive environment, is essential for therapeutic cancer vaccines in triggering an adequate antitumor immune response. In this review, we aim to review the challenges in and strategies for enhancing the efficacy of therapeutic vaccines. We start with the summary of the available tumor antigens and their properties and then the optimal strategies for vaccine delivery. Subsequently, the vaccine adjuvants focused on the intrinsic adjuvant properties of nanostructures are further discussed. Finally, we summarize the combination strategies with therapeutic cancer vaccines and discuss their positive impact in cancer immunity.

Artificial Metalloprotein Nanoanalogues: In Situ Catalytic Production of Oxygen to Enhance Photoimmunotherapeutic Inhibition of Primary and Abscopal Tumor Growth

Photoimmunotherapy (PIT) has shown enormous potential in not only eliminating primary tumors, but also inhibiting abscopal tumor growth. However, the efficacy of PIT is greatly limited by tumor hypoxia, which causes the attenuation of phototherapeutic efficacy and is a feature of the immunosuppressive tumor microenvironment (TME). In this study, one type of brand-new artificial metalloprotein nanoanalogues is developed via reasonable integration of a "phototherapy-enzymatic" RuO₂ and a model antigen, ovalbumin (OVA) for enhanced PIT of cancers, namely, RuO₂ -hybridized OVA nanoanalogues (RuO₂ @OVA NAs). The RuO₂ @OVA NAs exhibit remarkable photothermal/photodynamic capabilities under the near-infrared light irradiation. More importantly, the photoacoustic imaging and immunofluorescence staining confirm that RuO₂ @OVA NAs can remarkably alleviate hypoxia via in situ catalysis of hydrogen peroxide overexpressed in the TME to produce oxygen (O₂ ). This ushers a prospect of concurrently enhancing photodynamic therapy and reversing the immunosuppressive TME. Also, OVA, as a supplement to the immune stimulation induced by phototherapy, can activate immune responses. Finally, further combination with the cytotoxic T-lymphocyte-associated protein 4 checkpoint blockade is reported to effectively eliminate the primary tumor and inhibit distant tumor growth via the abscopal effect of antitumor immune responses, prolonging the survival.

Choice of Nanovaccine Delivery Mode Has Profound Impacts on the Intralymph Node Spatiotemporal Distribution and Immunotherapy Efficacy

Nanovaccines have attracted booming interests in vaccinology studies, but the profound impacts of their delivery mode on immune response remain unrealized. Herein, immunostimulatory CpG-modified tumor-derived nanovesicles (CNVs) are used as a nanovaccine testbed to initially evaluate the impacts of three distinct delivery modes, including mono-pulse CNVs, staggered-pulse CNVs, and gel-confined CNVs. Fundamentally, delivery mode has enormous impacts on the immunomodulatory effects, altering the spatiotemporal distribution of nanovaccine residence and dendritic cell-T cell interaction in lymph nodes, and finally affecting subsequent T cell-mediated immune performance. As a result, the gel-confined delivery mode offers the best therapeutic performance in multiple tumor models. When extending evaluation to examine how the various delivery modes impact the performance of liposome-based nanovaccines, similar trends in intralymph node distribution and antitumor effect are observed. This work provides a strong empirical foundation that nanovaccine researchers should position delivery mode near the top of their considerations for the experimental design, which should speed up nanovaccine development and facilitate efficient selection of appropriate delivery modes in the clinic.

Nanomedicine-based tumor photothermal therapy synergized immunotherapy

The emerging anti-tumor immunotherapy has made significant progress in clinical application. However, single immunotherapy is not effective for all anti-tumor treatments, owing to the low objective response rate and the risk of immune-related side effects. Meanwhile, photothermal therapy (PTT) has attracted significant attention because of its non-invasiveness, spatiotemporal controllability and small side effects. Combining PTT with immunotherapy overcomes the issue that single photothermal therapy cannot eradicate tumors with metastasis and recurrence. However, it improves the therapeutic effect of immunotherapy, as the photothermal therapy usually promotes release of tumor-related antigens, triggers immune response by the immunogenic cell death (ICD), thereby, endowing unique synergistic mechanisms for cancer therapy. This review summarizes recent research advances in utilizing nanomedicines for PTT in combination with immunotherapy to improve the outcome of cancer treatment. The strategies include immunogenic cell death, immune agonists and cancer vaccines, immune checkpoint blockades and tumor specific monoclonal antibodies, and small-molecule immune inhibitors. The combination of synergized PTT-immunotherapy with other therapeutic strategies is also discussed.

Albumin-Based LL37 Peptide Nanoparticles as a Sustained Release System against Pseudomonas aeruginosa Lung Infection

Pseudomonas aeruginosa (PA) has emerged as a pressing challenge to pulmonary infection and lung damage. The LL37 peptide is an efficient antimicrobial agent against PA strains, but its application is limited because of fast clearance in vivo, biosafety concerns, and low bioavailability. Thus, an albumin-based nanodrug delivery system with reduction sensitivity was developed by forming intermolecular disulfide bonds to increase in vivo LL37 performance against PA. Cationic LL37 can be efficiently encapsulated via electrostatic interactions to exert improved antimicrobial effects. The LL37 peptide exhibits greater than 48 h of sustained released from LL37 peptide nanoparticles (LL37 PNP), and prolonged antimicrobial effects were noted as the incubation time increased. Levels of inflammatory cytokines secreted by peritoneal macrophages, including TNF-α and IL-6, were reduced significantly after LL37 PNP treatment following PA stimulation, indicating that LL37 PNP inhibits PA growth and exerts anti-inflammatory effects in vitro. In a murine model of acute PA lung infection, LL37 PNP significantly reduced TNF-α and IL-1β expression and alleviated lung damage. The accelerated clearance of PA indicates that LL37 PNP could improve PA lung infection and the subsequent inflammation response more efficiently compared with free LL37 peptide. In conclusion, this excellent biocompatible LL37 delivery strategy may serve as an alternative approach for the application of new types of clinical treatment in future.

A biomimetic antitumor nanovaccine based on biocompatible calcium pyrophosphate and tumor cell membrane antigens

Currently, the cancer immunotherapy has made great progress while antitumor vaccine attracts substantial attention. Still, the selection of adjuvants as well as antigens are always the most crucial issues for better vaccination. In this study, we proposed a biomimetic antitumor nanovaccine based on biocompatible nanocarriers and tumor cell membrane antigens. Briefly, endogenous calcium pyrophosphate nanogranules with possible immune potentiating effect are designed and engineered, both as delivery vehicles and adjuvants. Then, these nanocarriers are coated with lipids and B16-OVA tumor cell membranes, so the biomembrane proteins can serve as tumor-specific antigens. It was found that calcium pyrophosphate nanogranules themselves were compatible and possessed adjuvant effect, while membrane proteins including tumor associated antigen were transferred onto the nanocarriers. It was demonstrated that such a biomimetic nanovaccine could be well endocytosed by dendritic cells, promote their maturation and antigen-presentation, facilitate lymph retention, and trigger obvious immune response. It was confirmed that the biomimetic vaccine could induce strong T-cell response, exhibit excellent tumor therapy and prophylactic effects, and simultaneously possess nice biocompatibility. In general, the present investigation might provide insights for the further design and application of antitumor vaccines.

Mimetic Heat Shock Protein Mediated Immune Process to Enhance Cancer Immunotherapy

Inspired by heat shock proteins (HSPs), a self-assembly nanochaperone (nChap) is developed as a novel nanovaccine for boosting antitumor immune responses. Taking advantage of HSP-like microdomains and surface-decorated mannose, this nChap can efficiently capture antigens and ferry them into the dendritic cells (DCs). Subsequently, the nChap can blast lysosomes by transforming the structure and property of surface microdomains, thereby promoting antigen escape and enhancing their cross-presentation in cytoplasm. As a result, the nChap-based nanovaccine can elicit both CD4+ and CD8+ T cell-based immune responses and shows an excellent preventive effect on melanoma. Further combination of the nanovaccine with antiprogrammed death-1 (anti-PD-1) checkpoint blockade offers effective inhibition on the growth of already-established melanoma. Therefore, this nC ap-based nanovaccine provides a simple and robust strategy in mimicking HSPs to realize structure-assisted antigen capture, surface-receptor-mediated DC internalization, and both activation of humoral immunity and cellular immunity, promising for efficient cancer immunotherapy.

Bacterial extracellular vesicle-coated multi-antigenic nanovaccines protect against drug-resistant Staphylococcus aureus infection by modulating antigen processing and presentation pathways

Background: Vaccination provides an alternative to antibiotics in addressing drug-resistant Staphylococcus aureus (S. aureus) infection. However, vaccine potency is often limited by a lack of antigenic breadth and a demand on the generation of antibody responses alone.

Methods: In this study, bacterial extracellular vesicles (EVs) coating indocyanine green (ICG)-loaded magnetic mesoporous silica nanoparticles (MSN) were constructed as multi-antigenic vaccines (EV/ICG/MSN) with the ability to modulate antigen presentation pathways in dendritic cells (DCs) to induce cellular immune responses.

Results: Exposing the EV/ICG/MSNs to a laser could promote DC maturation and enhance the proteasome-dependent antigen presentation pathway by facilitating endolysosomal escape, improving proteasome activity, and elevating MHC-I expression. Immunization by EV/ICG/MSNs with laser irradiation in vivo triggered improved CD8⁺ T cell responses while maintaining CD4⁺ T cell responses and humoral immunity. In addition, in vivo tracking data revealed that the vaccine could be efficiently transported from the injection site into lymph nodes. Skin infection experiments showed that the vaccine not only prevented and treated superficial infection but also decreased bacterial invasiveness, thus strongly suggesting that EV/ICG/MSNs were effective in preventing complications resulting from the introduction of S. aureus infections.

Conclusion: This multi-antigenic nanovaccine-based modulation of antigen presentation pathways provides an effective strategy against drug-resistant S. aureus infection.

Turning weakness into strength: Albumin nanoparticle-redirected amphotericin B biodistribution for reducing nephrotoxicity and enhancing antifungal activity

As the gold standard treatment for invasive fungal infection, amphotericin B (AmB) is limited by its severe nephrotoxicity. It has been shown that AmB complex with albumin in vivo forms a sub-10 nm nanocomplex within kidney excretion size range and eventually induces the nephrotoxicity. This study presents an approach to take advantage of the "weakness" of such unique interaction between AmB and albumin to form AmB nanocomplex beyond the size range of kidney excretion. Herein, a novel strategy was developed by directly assembling molecular BSA into larger-sized nanostructures with the reconstructed intermolecular disulfide bond and hydrophobic interaction. The rich binding sites of AmB within BSA nanostructures enabled the efficient AmB loading and forming nanoparticle (AmB-NP) which exceeds the size range of kidney excretion (~ 60 nm). We found nanoassembly with BSA redirected biodistribution of AmB with a 2.8-fold reduction of drug accumulation in the kidney and significantly improved its renal impairment in mice. Furthermore, we found that nanoassembly with BSA significantly increased the biodistribution of AmB in brain and endowed it 100-folds increase in pharmacological effect against meningoencephalitis caused by common fungal pathogen Cryptococcus neoformans. Together, this study not merely overcomes the nephrotoxicity of AmB using its "weakness" by a nanoassembly method, and provides a new strategy for reducing toxicity of drugs with high albumin binding rate in vivo.

Personalized neoantigen vaccination with synthetic long peptides: recent advances and future perspectives

Therapeutic cancer vaccines are one of the most promising strategies of immunotherapy. Traditional vaccines consisting of tumor-associated antigens have met with limited success. Recently, neoantigens derived from nonsynonymous mutations in tumor cells have emerged as alternatives that can improve tumor-specificity and reduce on-target off-tumor toxicity. Synthetic peptides are a common platform for neoantigen vaccines. It has been suggested that extending short peptides into long peptides can overcome immune tolerance and induce both CD4⁺ and CD8⁺ T cell responses. This review will introduce the history of long peptide-based neoantigen vaccines, discuss their advantages, summarize current preclinical and clinical developments, and propose future perspectives.

Nucleic acid nanotechnology for cancer treatment

Cancer is one of the most prevalent potentially lethal diseases. With the increase in the number of investigations into the uses of nanotechnology, many nucleic acid (NA)-based nanostructures such as small interfering RNA, microRNA, aptamers, and immune adjuvant NA have been applied to treat cancer. Here, we discuss studies on the applications of NA in cancer treatment, recent research trends, and the limitations and prospects of specific NA-mediated gene therapy and immunotherapy for cancer treatment. The NA structures used for cancer therapy consist only of NA or hybrids comprising organic or inorganic substances integrated with functional NA. We also discuss delivery vehicles for therapeutic NA and anti-cancer agents, and recent trends in NA-based gene therapy and immunotherapy against cancer.