Subcutaneous Nanodisc Vaccination with Neoantigens for Combination Cancer Immunotherapy

High-density lipoprotein-like nanoparticles with cationic cholesterol derivatives for siRNA delivery

A new approach to siRNA delivery using high-density lipoprotein-like nanoparticles (HDL NPs) was investigated, incorporating oligoamine and cholesterol-derived cationic lipids (CLs) to associate siRNA with the carrier. Newly designed or commercially available compounds, including GL67 and 3-β-[N-(N',N'-dimethylaminoethane)-carbamoyl]cholesterol (DC-Cholesterol), were tested for siRNA binding, cytotoxicity, and siRNA cellular uptake. GL67 emerged as the most promising CL for siRNA delivery via HDL NPs. While it contributed to substantial siRNA uptake and cytosolic delivery in HepG2 cells, gene silencing remained limited, indicating a need for further optimization. Despite this, the study highlights the potential of positively charged cholesterol derivatives for siRNA delivery using HDL NPs. An analysis of the relationship between CL head group structure and HDL NPs' siRNA binding efficiency and cytotoxicity showed that factors such as oligoamine molecule conjugation site, linker type, amine group ethylation, and alkyl chain length between amine groups are crucial for optimizing CL design. Furthermore, the phospholipid environment surrounding CLs significantly influences HDL NPs' performance, particularly in siRNA cellular uptake. The study also revealed that intracellular siRNA trafficking varies by cell type, emphasizing the importance of customizing HDL NP formulations for specific cells. These insights are important for designing more effective HDL NPs for siRNA therapeutic delivery.

Cancer vaccines: current status and future directions

Cancer continues to be a major global health burden, with high morbidity and mortality. Building on the success of immune checkpoint inhibitors and adoptive cellular therapy, cancer vaccines have garnered significant interest, but their clinical success remains modest. Benefiting from advancements in technology, many meticulously designed cancer vaccines have shown promise, warranting further investigations to reach their full potential. Cancer vaccines hold unique benefits, particularly for patients resistant to other therapies, and they offer the ability to initiate broad and durable T cell responses. In this review, we highlight the antigen selection for cancer vaccines, introduce the immune responses induced by vaccines, and propose strategies to enhance vaccine immunogenicity. Furthermore, we summarize key features and notable clinical advances of various vaccine platforms. Lastly, we delve into the mechanisms of tumor resistance and explore the potential benefits of combining cancer vaccines with standard treatments and other immunomodulatory approaches to improve vaccine efficacy.

Current Landscape of Therapeutic Cancer Vaccines

Cancer vaccines aim to harness the immune system for prevention or treatment of the disease. This is achieved by immunizing against target antigens that are specific/associated with cancer. Myriad of particulate materials or cell-based strategies have been developed to induce immune responses against cancer antigens, using protein/peptide antigens, DNA or RNA, viral antigens, viral or bacterial vectors, embryonic material, whole tumor lysate, dendritic cells, red blood cells, exosomes, liposomes, engineered bioinspired and biomimetic vaccines and glycosylation-based vaccines. Several key factors affect the safety and efficacy of therapeutic cancer vaccines, including identification of potent neoantigens, dosage, adjuvant and regimen of immunization, route of administration and delivery methods, as well as overcoming intrinsic and extrinsic resistance mechanisms. More recently, novel approaches for improving cancer vaccines have been explored, such as intratumoral vaccinations, oncolytic viruses, and combination immunotherapies. This chapter aims to provide a glimpse into some of the most common approaches for therapeutic cancer vaccines.

Nanoparticles-Assisted Peptide Cancer Vaccine Delivery

Efficient delivery of tumor antigen peptides and adjuvants to dendritic cells in lymphoid organs is critical for eliciting potent tumor antigen-specific CD8+ T cell responses. However, soluble antigens and adjuvants often suffer from rapid clearance and fail to induce strong T-cell responses. Synthetic high-density lipoproteins (sHDL) nanodiscs, which are 10-nm discoidal nanoparticles, have been shown to facilitate the co-delivery of peptide antigens and adjuvants to lymph nodes and induce strong and durable antigen presentation by dendritic cells, which markedly improve the overall magnitude of antigen-specific T cell responses. Here we summarize the methods for preparing sHDL-based peptide cancer vaccines and protocols for analyzing the T cell responses against different tumor antigens. We envision that these methods will be helpful in developing and assessing other nanoparticle-based peptide cancer vaccines in the future.

Development of a Versatile Cancer Vaccine Format Targeting Antigen-Presenting Cells Using Proximity-Based Sortase A-Mediated Ligation of T-Cell Epitopes

Cancer vaccines are a promising strategy to increase tumor-specific immune responses in patients who do not adequately respond to checkpoint inhibitors. Cancer vaccines that contain patient-specific tumor antigens are most effective but also necessitate the production of patient-specific vaccines. This study aims to develop a versatile cancer vaccine format in which patient-specific tumor antigens can be site-specifically conjugated by a proximity-based Sortase A (SrtA)-mediated ligation (PBSL) approach to antibodies that specifically bind to antigen-presenting cells to stimulate immune responses. DEC205 and CD169 are both receptors expressed on antigen-presenting cells that can be targeted to deliver antigens and stimulate T-cell responses. We used the CRISPR/HDR platform to produce mouse heavy chain IgG2a antibodies with DEC205 or CD169 specificity containing an SrtA recognition motif followed by a SpyTag at the C-terminus. Using a recombinant protein of SrtA linked to SpyCatcher, we applied proximity-based SrtA-mediated ligation to ligate fluorescein isothiocyanate (FITC)-labeled or antigenic peptides to the antibodies. Ligated antibodies bound to DEC205-expressing dendritic cells or CD169-expressing macrophages both in vitro and in vivo. More importantly, immunization with DEC205- or CD169-specific Abs linked to T-cell epitopes efficiently stimulated T-cell responses in vivo. To conclude, we have developed a cancer vaccine format using PBSL that enables the rapid incorporation of tumor antigens and could potentially be implemented for the synthesis of personalized cancer vaccines.

Enhancing cancer immunotherapy with mannose mimicking glycopolymer nanoparticles induced activation of Dendritic cells

Cancer immunotherapy leverages the immune system's inherent capacity to combat malignancies. However, effective stimulation of Dendritic cells (DCs) is challenging due to their limited distribution and the immune-suppressive tumor microenvironment. Thus, targeting mannose receptors, which are highly expressed on DCs, represents a promising strategy. This study investigates the development of mannose-based glycopolymer nanoparticles to induce activation of DCs through enhanced antigen presentation. A novel ABA-type triblock bioconjugated glycopolymer (PMn-b-PCL-b-PMn), which mimics mannose was synthesized. This polymer was further modified with Dihexadecyldimethylammonium bromide (DHDAB) to prepare cationic nanoparticles (CMNP) for gene delivery of pCMV-TRP2, an antigenic marker for both melanoma and glioblastoma. The immune response generated by CMNP and the CMNP-TRP2 polyplex was compared to an untreated control following subcutaneous injection in mice. Post-injection cytometric analysis revealed robust DC activation and increased T-cell populations in secondary lymphoid organs, including the spleen and lymph nodes. These findings suggest that CMNP can serve as a potent biomimicking vaccination vehicle against cancer, enhancing the immune response through targeted DCs activation.

Biomaterial-Based In Situ Cancer Vaccines

Cancer immunotherapies have reshaped the paradigm for cancer treatment over the past decade. Among them, therapeutic cancer vaccines that aim to modulate antigen-presenting cells and subsequent T cell priming processes are among the first FDA-approved cancer immunotherapies. However, despite showing benign safety profiles and the capability to generate antigen-specific humoral and cellular responses, cancer vaccines have been limited by the modest therapeutic efficacy, especially for immunologically cold solid tumors. One key challenge lies in the identification of tumor-specific antigens, which involves a costly and lengthy process of tumor cell isolation, DNA/RNA extraction, sequencing, mutation analysis, epitope prediction, peptide synthesis, and antigen screening. To address these issues, in situ cancer vaccines have been actively pursued to generate endogenous antigens directly from tumors and utilize the generated tumor antigens to elicit potent cytotoxic T lymphocyte (CTL) response. Biomaterials-based in situ cancer vaccines, in particular, have achieved significant progress by taking advantage of biomaterials that can synergize antigens and adjuvants, troubleshoot delivery issues, home, and manipulate immune cells in situ. This review will provide an overview of biomaterials-based in situ cancer vaccines, either living or artificial materials, under development or in the clinic, and discuss the design criteria for in situ cancer vaccines.

Nanovaccines: Immunogenic tumor antigens, targeted delivery, and combination therapy to enhance cancer immunotherapy

Nanovaccines have been designed to overcome the limitations associated with conventional vaccines. Effective delivery methods such as engineered carriers or smart nanoparticles (NPs) are critical requisites for inducing self-tolerance and optimizing vaccine immunogenicity with minimum side effects. NPs can be used as adjuvants, immunogens, or nanocarriers to develop nanovaccines for efficient antigen delivery. Multiloaded nanovaccines carrying multiple tumor antigens along with immunostimulants can effectively increase immunity against tumor cells. They can be biologically engineered to boost interactions with dendritic cells and to allow a gradual and constant antigen release. Modifying NPs surface properties, using high-density lipoprotein-mimicking nanodiscs, and developing nano-based artificial antigen-presenting cells such as dendritic cell-derived-exosomes are amongst the new developed technologies to enhance antigen-presentation and immune reactions against tumor cells. The present review provides an overview on the different perspectives, improvements, and barriers of successful clinical application of current cancer therapeutic and vaccination options. The immunomodulatory effects of different types of nanovaccines and the nanoparticles incorporated into their structure are described. The advantages of using nanovaccines to prevent and treat common illnesses such as AIDS, malaria, cancer and tuberculosis are discussed. Further, potential paths to develop optimal cancer vaccines are described. Given the immunosuppressive characteristics of both cancer cells and the tumor microenvironment, applying immunomodulators and immune checkpoint inhibitors in combination with other conventional anticancer therapies are necessary to boost the effectiveness of the immune response.

The immunogenicity of p24 protein from HIV-1 virus is strongly supported and modulated by coupling with liposomes and mannan

Anti-viral and anti-tumor vaccines aim to induce cytotoxic CD8+ T cells (CTL) and antibodies. Conserved protein antigens, such as p24 from human immunodeficiency virus, represent promising component for elicitation CTLs, nevertheless with suboptimal immunogenicity, if formulated as recombinant protein. To enhance immunogenicity and CTL response, recombinant proteins may be targeted to dendritic cells (DC) for cross presentation on MHCI, where mannose receptor and/or other lectin receptors could play an important role. Here, we constructed liposomal carrier-based vaccine composed of recombinant p24 antigen bound by metallochelating linkage onto surface of nanoliposomes with surface mannans coupled by aminooxy ligation. Generated mannosylated proteonanoliposomes were analyzed by dynamic light scattering, isothermal titration, and electron microscopy. Using murine DC line MutuDC and murine bone marrow derived DC (BMDC) we evaluated their immunogenicity and immunomodulatory activity. We show that p24 mannosylated proteonanoliposomes activate DC for enhanced MHCI, MHCII and CD40, CD80, and CD86 surface expression both on MutuDC and BMDC. p24 mannosylated liposomes were internalized by MutuDC with p24 intracellular localization within 1 to 3 h. The combination of metallochelating and aminooxy ligation could be used simultaneously to generate nanoliposomal adjuvanted recombinant protein-based vaccines versatile for combination of recombinant antigens relevant for antibody and CTL elicitation.

Self-Assembled STING-Activating Coordination Nanoparticles for Cancer Immunotherapy and Vaccine Applications

The cGAS-STING pathway plays a crucial role in innate immune activation against cancer and infections, and STING agonists based on cyclic dinucleotides (CDN) have garnered attention for their potential use in cancer immunotherapy and vaccines. However, the limited drug-like properties of CDN necessitate an efficient delivery system to the immune system. To address these challenges, we developed an immunostimulatory delivery system for STING agonists. Here, we have examined aqueous coordination interactions between CDN and metal ions and report that CDN mixed with Zn2+ and Mn2+ formed distinctive crystal structures. Further pharmaceutical engineering led to the development of a functional coordination nanoparticle, termed the Zinc-Mn-CDN Particle (ZMCP), produced by a simple aqueous one-pot synthesis. Local or systemic administration of ZMCP exerted robust antitumor efficacy in mice. Importantly, recombinant protein antigens from SARS-CoV-2 can be simply loaded during the aqueous one-pot synthesis. The resulting ZMCP antigens elicited strong cellular and humoral immune responses that neutralized SARS-CoV-2, highlighting ZMCP as a self-adjuvant vaccine platform against COVID-19 and other infectious pathogens. Overall, this work establishes a paradigm for developing translational coordination nanomedicine based on drug-metal ion coordination and broadens the applicability of coordination medicine for the delivery of proteins and other biologics.

Design and Evaluation of Synthetic Delivery Formulations for Peptide-Based Cancer Vaccines

With the recent advances in neoantigen identification, peptide-based cancer vaccines offer substantial potential in the field of immunotherapy. However, rapid clearance, low immunogenicity, and insufficient antigen-presenting cell (APC) uptake limit the efficacy of peptide-based cancer vaccines. This review explores the barriers hindering vaccine efficiency, highlights recent advancements in synthetic delivery systems, and features strategies for the key delivery steps of lymph node (LN) drainage, APC delivery, cross-presentation strategies, and adjuvant incorporation. This paper also discusses the design of preclinical studies evaluating vaccine efficiency, including vaccine administration routes and murine tumor models.

The quest for nanoparticle-powered vaccines in cancer immunotherapy

Despite recent advancements in cancer treatment, this disease still poses a serious threat to public health. Vaccines play an important role in preventing illness by preparing the body's adaptive and innate immune responses to combat diseases. As our understanding of malignancies and their connection to the immune system improves, there has been a growing interest in priming the immune system to fight malignancies more effectively and comprehensively. One promising approach involves utilizing nanoparticle systems for antigen delivery, which has been shown to potentiate immune responses as vaccines and/or adjuvants. In this review, we comprehensively summarized the immunological mechanisms of cancer vaccines while focusing specifically on the recent applications of various types of nanoparticles in the field of cancer immunotherapy. By exploring these recent breakthroughs, we hope to identify significant challenges and obstacles in making nanoparticle-based vaccines and adjuvants feasible for clinical application. This review serves to assess recent breakthroughs in nanoparticle-based cancer vaccinations and shed light on their prospects and potential barriers. By doing so, we aim to inspire future immunotherapies for cancer that harness the potential of nanotechnology to deliver more effective and targeted treatments.

Designing nanodiscs as versatile platforms for on-demand therapy

Nowadays, there has been an increasing utilization of nanomedicines for disease treatment. Nanodiscs (NDs) have emerged as a novel platform technology that garners significant attention in biomedical research and drug discovery. NDs are nanoscale phospholipid bilayer discs capable of incorporating membrane proteins and lipids within a native-like environment. They are assembled using amphiphilic biomacromolecular materials, such as apolipoprotein A1 or membrane scaffold proteins (MSPs), peptides, and styrene-maleic acid polymers (SMAs). NDs possess well-defined sizes and shapes, offering a stable, homogeneous, and biologically relevant environment for studying membrane proteins and lipids. Their unique properties have made them highly desirable for diverse applications, including cancer immunotherapy, vaccine development, antibacterial and antiviral therapy, and treating Alzheimer's disease (AD) and diabetes-related conditions. This review discusses the classifications, advantages, and applications of NDs in disease therapy.

Hyaluronic acid-antigens conjugates trigger potent immune response in both prophylactic and therapeutic immunization in a melanoma model

Immunotherapy of advanced melanoma has encountered significant hurdles in terms of clinical efficacy. Here, we designed a clinically translatable hyaluronic acid (HA)-based vaccine delivering a combination of major histocompatibility complex (MHC) class I- and class II-restricted melanoma antigens (TRP2 and Gp100, respectively) conjugated to HA. HA-nanovaccine (HA-TRP2-Gp100 conjugate) exhibited tropism in the lymph nodes and promoted stimulation of the immune response (2.3-fold higher than the HA+TRP2+Gp100). HA-nanovaccine significantly delayed the growth of B16F10 melanoma and extended survival in both the prophylactic and therapeutic settings (median survival of 22 and 27, respectively, vs 17 days of the untreated group). Moreover, mice prophylactically treated with the HA-nanovaccine displayed significantly higher CD8+ and CD4+ T-cell/Treg ratios in both the spleen and tumor at day 16, suggesting that the HA-nanovaccine overcame the immunosuppressive tumor microenvironment. Superior infiltration of active CD4+ and CD8+ T cells was observed at the endpoint. This study supports the conclusion that HA potentiates the effect of a combination of MHC I and MHC II antigens via a potent immune response against melanoma.

Poly-γ-glutamic acid nanoparticles as adjuvant and antigen carrier system for cancer vaccination

Vaccination is an innovative strategy for cancer treatment by leveraging various components of the patients' immunity to boost an anti-tumor immune response. Rationally designed nanoparticles are well suited to maximize cancer vaccination by the inclusion of immune stimulatory adjuvants. Also, nanoparticles might control the pharmacokinetics and destination of the immune potentiating compounds. Poly-γ-glutamic acid (γ-PGA) based nanoparticles (NPs), which have a natural origin, can be easily taken up by dendritic cells (DCs), which leads to the secretion of cytokines which ameliorates the stimulation capacity of T cells. The intrinsic adjuvant properties and antigen carrier properties of γ-PGA NPs have been the focus of recent investigations as they can modulate the tumor microenvironment, can contribute to systemic anti-tumor immunity and subsequently inhibit tumor growth. This review provides a comprehensive overview on the potential of γ-PGA NPs as antigen carriers and/or adjuvants for anti-cancer vaccination.

Synthesis of Erythrocyte Nanodiscs for Bacterial Toxin Neutralization

Nanodiscs are a compelling nanomedicine platform due to their ultrasmall size and distinct disc shape. Current nanodisc formulations are made primarily with synthetic lipid bilayers and proteins. Here, we report a cellular nanodisc made with human red blood cell (RBC) membrane (denoted "RBC-ND") and show its effective neutralization against bacterial toxins. In vitro, RBC-ND neutralizes the hemolytic activity and cytotoxicity caused by purified α-toxin or complex whole secreted proteins (wSP) from methicillin-resistant Staphylococcus aureus bacteria. In vivo, RBC-ND confers significant survival benefits for mice intoxicated with α-toxin or wSP in both therapeutic and prevention regimens. Moreover, RBC-ND shows good biocompatibility and biosafety in vivo. Overall, RBC-ND distinguishes itself by inheriting the biological functions of the source cell membrane for bioactivity. The design strategy of RBC-ND can be generalized to other types of cell membranes for broad applications.

Emerging peptide-based nanovaccines: From design synthesis to defense against cancer and infection

Peptide-based vaccines, which form one of the most potent vaccine platforms, offer exclusive advantages over classical vaccines that use whole organisms or proteins. However, peptides alone are still poor stability and weak immunogenicity, thus need a delivery system that can overcome these shortcomings. Currently, nanotechnology has been extensively utilized to address this issue. Nanovaccines, as new formulations of vaccines using nanoparticles (NPs) as carriers or adjuvants, are undergoing development instead of conventional vaccines. Indeed, peptide-based nanovaccine is a rapidly developing field of research that is emerging out of the confluence of antigenic peptides with the nano-delivery system. In this review, we shed light on the rational design and preparation strategies based on various nanomaterials of peptide-based nanovaccines, and we spotlight progress in the development of peptide-based nanovaccines against cancer and infectious diseases. Finally, the future prospects for development of peptide-based nanovaccines are presented.

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.

New advances in pharmaceutical strategies for sensitizing anti-PD-1 immunotherapy and clinical research

Attempts have been made continuously to use nano-drug delivery system (NDDS) to improve the effect of antitumor therapy. In recent years, especially in the application of immunotherapy represented by antiprogrammed death receptor 1 (anti-PD-1), it has been vigorously developed. Nanodelivery systems are significantly superior in a number of aspects including increasing the solubility of insoluble drugs, enhancing their targeting ability, prolonging their half-life, and reducing side effects. It can not only directly improve the efficacy of anti-PD-1 immunotherapy, but also indirectly enhance the antineoplastic efficacy of immunotherapy by boosting the effectiveness of therapeutic modalities such as chemotherapy, radiotherapy, photothermal, and photodynamic therapy (PTT/PDT). Here, we summarize the studies published in recent years on the use of nanotechnology in pharmaceutics to improve the efficacy of anti-PD-1 antibodies, analyze their characteristics and shortcomings, and combine with the current clinical research on anti-PD-1 antibodies to provide a reference for the design of future nanocarriers, so as to further expand the clinical application prospects of NDDSs. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

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.

Cellular Nanodiscs Made from Bacterial Outer Membrane as a Platform for Antibacterial Vaccination

Vaccination has become an increasingly attractive strategy for protecting against antibiotic-resistant infections. Nanovaccines based on the outer membrane from Gram-negative bacteria are appealing due to their multiantigenic nature and inherent immunogenicity. Here, we develop cellular nanodiscs made of bacterial outer membrane (OM-NDs), as a platform for antibacterial vaccination. Using Pseudomonas aeruginosa as a model pathogen, the resulting OM-NDs can effectively interact with antigen-presenting cells, exhibiting accelerated uptake and an improved capacity for immune stimulation. With their small size, the OM-NDs are also capable of efficiently transporting to the lymph nodes after in vivo administration. As a result, the nanovaccine is effective at eliciting potent humoral and cellular immune responses against P. aeruginosa. In a murine model of pneumonia, immunization with OM-NDs confers strong protection against subsequent lung infection, resulting in improved survival, reduced bacterial loads, and alleviation of immune overactivation. Overall, this report illustrates the advantages of cellular nanodiscs, which can be readily generalized to other pathogens and may be applied toward other biomedical applications.

Nanomedicine and versatile therapies for cancer treatment

The higher prevalence of cancer is related to high rates of mortality and morbidity worldwide. By virtue of the properties of matter at the nanoscale, nanomedicine is proven to be a powerful tool to develop innovative drug carriers with greater efficacies and fewer side effects than conventional therapies. In this review, different nanocarriers for controlled drug release and their routes of administration have been discussed in detail, especially for cancer treatment. Special emphasis has been given on the design of drug delivery vehicles for sustained release and specific application methods for targeted delivery to the affected areas. Different polymeric vehicles designed for the delivery of chemotherapeutics have been discussed, including graft copolymers, liposomes, hydrogels, dendrimers, micelles, and nanoparticles. Furthermore, the effect of dimensional properties on chemotherapy is vividly described. Another integral section of the review focuses on the modes of administration of nanomedicines and emerging therapies, such as photothermal, photodynamic, immunotherapy, chemodynamic, and gas therapy, for cancer treatment. The properties, therapeutic value, advantages, and limitations of these nanomedicines are highlighted, with a focus on their increased performance versus conventional molecular anticancer therapies.

Engineering neoantigen vaccines to improve cancer personalized immunotherapy

Immunotherapy treatments harnessing the immune system herald a new era of personalized medicine, offering considerable benefits for cancer patients. Over the past years, tumor neoantigens emerged as a rising star in immunotherapy. Neoantigens are tumor-specific antigens arising from somatic mutations, which are proceeded and presented by the major histocompatibility complex on the cell surface. With the advancement of sequencing technology and bioinformatics engineering, the recognition of neoantigens has accelerated and is expected to be incorporated into the clinical routine. Currently, tumor vaccines against neoantigens mainly encompass peptides, DNA, RNA, and dendritic cells, which are extremely specific to individual patients. Due to the high immunogenicity of neoantigens, tumor vaccines could activate and expand antigen-specific CD4+ and CD8+ T cells to intensify anti-tumor immunity. Herein, we introduce the origin and prediction of neoantigens and compare the advantages and disadvantages of multiple types of neoantigen vaccines. Besides, we review the immunizations and the current clinical research status in neoantigen vaccines, and outline strategies for enhancing the efficacy of neoantigen vaccines. Finally, we present the challenges facing the application of neoantigens.

Lipid Nanoparticles for mRNA Delivery to Enhance Cancer Immunotherapy

Messenger RNA (mRNA) is being developed by researchers as a novel drug for the treatment or prevention of many diseases. However, to enable mRNA to fully exploit its effects in vivo, researchers need to develop safer and more effective mRNA delivery systems that improve mRNA stability and enhance the ability of cells to take up and release mRNA. To date, lipid nanoparticles are promising nanodrug carriers for tumor therapy, which can significantly improve the immunotherapeutic effects of conventional drugs by modulating mRNA delivery, and have attracted widespread interest in the biomedical field. This review focuses on the delivery of mRNA by lipid nanoparticles for cancer treatment. We summarize some common tumor immunotherapy and mRNA delivery strategies, describe the clinical advantages of lipid nanoparticles for mRNA delivery, and provide an outlook on the current challenges and future developments of this technology.

Bifunctional hetero di-disc for broad-spectrum influenza neutralization

Nanodiscs containing sialic acid, which binds the hemagglutinin of the influenza virus, rupture the viral envelope and entrap viral ribonucleoproteins in the endolysosome. While nanodiscs are potent antiviral platforms, ganglioside GD1a containing α2,3-sialic acid does not cover all virus strains. When two nanodiscs containing different receptors 6'-sialyllactose and GD1a were mixed, one nanodisc inhibited the function of the other. A nanodisc loaded with two different receptors exhibited a biased activity toward only one receptor precluding the generation of a multifunctional nanodisc. Here, we suggest hetero di-disc, in which two nanodiscs loaded with each receptor were conjugated through protein trans-splicing for a broad-spectrum antiviral. The hetero di-disc showed strong antiviral activity in vitro and in vivo. Our results suggested that hetero di-discs not only expanded the inhibitory spectrum of nanodiscs but also enabled nanodisc-based delivery of multiple ligands without interference.

Single-component nanodiscs via the thermal folding of amphiphilic graft copolymers with the adjusted flexibility of the main chain

Nanodiscs have attracted considerable attention as structural scaffolds for membrane-protein research and as biomaterials in e.g. drug-delivery systems. However, conventional disc-fabrication methods are usually laborious, and disc fabrication via the self-assembly of amphiphiles is difficult. Herein, we report the formation of polymer nanodiscs based on the self-assembly of amphiphilic graft copolymers by adjusting the persistence length of the main chain. Amphiphilic graft copolymers with a series of different main-chain persistence lengths were prepared and these formed, depending on the persistence length, either rods, discs, or vesicles. Notably, polymer nanodiscs were formed upon heating a chilled polymer solution without the need for any additives, and the thus obtained nanodiscs were used to solubilize a membrane protein during cell-free protein synthesis. Given the simplicity of this disc-fabrication method and the ability of these discs to solubilize membrane proteins, this study considerably expands the fundamental and practical scope of graft-copolymer nanodiscs and demonstrates their utility as tools for studying the structure and function of membrane proteins.

Nanodiscs: a versatile nanocarrier platform for cancer diagnosis and treatment

Cancer therapy is a significant challenge due to insufficient drug delivery to the cancer cells and non-selective killing of healthy cells by most chemotherapy agents. Nano-formulations have shown great promise for targeted drug delivery with improved efficiency. The shape and size of nanocarriers significantly affect their transport inside the body and internalization into the cancer cells. Non-spherical nanoparticles have shown prolonged blood circulation half-lives and higher cellular internalization frequency than spherical ones. Nanodiscs are desirable nano-formulations that demonstrate enhanced anisotropic character and versatile functionalization potential. Here, we review the recent development of theranostic nanodiscs for cancer mitigation ranging from traditional lipid nanodiscs encased by membrane scaffold proteins to newer nanodiscs where either the membrane scaffold proteins or the lipid bilayers themselves are replaced with their synthetic analogues. We first discuss early cancer detection enabled by nanodiscs. We then explain different strategies that have been explored to carry a wide range of payloads for chemotherapy, cancer gene therapy, and cancer vaccines. Finally, we discuss recent progress on organic-inorganic hybrid nanodiscs and polymer nanodiscs that have the potential to overcome the inherent instability problem of lipid nanodiscs.

Emerging biomaterial-based strategies for personalized therapeutic in situ cancer vaccines

Landmark successes in oncoimmunology have led to development of therapeutics boosting the host immune system to eradicate local and distant tumors with impactful tumor reduction in a subset of patients. However, current immunotherapy modalities often demonstrate limited success when involving immunologically cold tumors and solid tumors. Here, we describe the role of various biomaterials to formulate cancer vaccines as a form of cancer immunotherapy, seeking to utilize the host immune system to activate and expand tumor-specific T cells. Biomaterial-based cancer vaccines enhance the cancer-immunity cycle by harnessing cellular recruitment and activation against tumor-specific antigens. In this review, we discuss biomaterial-based vaccine strategies to induce lymphocytic responses necessary to mediate anti-tumor immunity. We focus on strategies that selectively attract dendritic cells via immunostimulatory gradients, activate them against presented tumor-specific antigens, and induce effective cross-presentation to T cells in secondary lymphoid organs, thereby generating immunity. We posit that personalized cancer vaccines are promising targets to generate long-term systemic immunity against patient- and tumor-specific antigens to ensure long-term cancer remission.

Nano-bio interfaces effect of two-dimensional nanomaterials and their applications in cancer immunotherapy

The field of two-dimensional (2D) nanomaterial-based cancer immunotherapy combines research from multiple subdisciplines of material science, nano-chemistry, in particular nano-biological interactions, immunology, and medicinal chemistry. Most importantly, the "biological identity" of nanomaterials governed by bio-molecular corona in terms of bimolecular types, relative abundance, and conformation at the nanomaterial surface is now believed to influence blood circulation time, bio-distribution, immune response, cellular uptake, and intracellular trafficking. A better understanding of nano-bio interactions can improve utilization of 2D nano-architectures for cancer immunotherapy and immunotheranostics, allowing them to be adapted or modified to treat other immune dysregulation syndromes including autoimmune diseases or inflammation, infection, tissue regeneration, and transplantation. The manuscript reviews the biological interactions and immunotherapeutic applications of 2D nanomaterials, including understanding their interactions with biological molecules of the immune system, summarizes and prospects the applications of 2D nanomaterials in cancer immunotherapy.

Amplifying STING activation by cyclic dinucleotide-manganese particles for local and systemic cancer metalloimmunotherapy

Nutritional metal ions play critical roles in many important immune processes. Hence, the effective modulation of metal ions may open up new forms of immunotherapy, termed as metalloimmunotherapy. Here, we demonstrate a prototype of cancer metalloimmunotherapy using cyclic dinucleotide (CDN) stimulator of interferon genes (STING) agonists and Mn2+. We screened various metal ions and discovered specific metal ions augmented STING agonist activity, wherein Mn2+ promoted a 12- to 77-fold potentiation effect across the prevalent human STING haplotypes. Notably, Mn2+ coordinated with CDN STING agonists to self-assemble into a nanoparticle (CDN-Mn2+ particle, CMP) that effectively delivered STING agonists to immune cells. The CMP, administered either by local intratumoural or systemic intravenous injection, initiated robust anti-tumour immunity, achieving remarkable therapeutic efficacy with minute doses of STING agonists in multiple murine tumour models. Overall, the CMP offers a new platform for local and systemic cancer treatments, and this work underscores the great potential of coordination nanomedicine for metalloimmunotherapy.

Enhancing therapeutic performance of personalized cancer vaccine via delivery vectors

In recent years, personalized cancer vaccines have gained increasing attention as emerging immunotherapies with the capability to overcome interindividual differences and show great benefits for individual patients in the clinic due to the highly tailored vaccine formulations. A large number of materials have been studied as delivery vectors to enhance the therapeutic performance of personalized cancer vaccines, including artificial materials, engineered microorganisms, cells and cell derivatives. These delivery vectors with distinct features are employed to change antigen biodistributions and to facilitate antigen uptake, processing and presentation, improving the strength, velocity, and duration of the immune response when delivered by different strategies. Here, we provide an overview of personalized cancer vaccine delivery vectors, describing their materials, physicochemical properties, delivery strategies and challenges for clinical transformation.

Nanolipoprotein particles for co-delivery of cystine-knot peptides and Fab-based therapeutics

Nanolipoprotein particles (NLPs) have been evaluated as an in vivo delivery vehicle for a variety of molecules of therapeutic interest. However, delivery of peptide-like drugs in combination with therapeutic Fabs has not yet been evaluated. In this study, we describe the development and characterization of cystine-knot peptide (CKP)-containing NLPs and Fab-CKP-NLP conjugates. CKPs were incorporated into NLPs using a self-assembly strategy. The trypsin inhibitor EETI-II, a model CKP, was produced with a C16 fatty acyl chain to enable incorporation of the CKP into the lipid bilayer core during NLP assembly. The CKP-NLP retained trypsin inhibitory function although the overall activity was reduced by ∼5 fold compared to free CKP, which was presumably due to steric hindrance. The NLP platform was also shown to accommodate up to ∼60 CKP molecules. Moreover, the stability of the CKP-NLP was comparable to the NLP control, displaying a relatively short half-life (∼1 h) in 50% serum at 37 °C. Therapeutic Fabs were also loaded onto the CKP-NLP by introducing thiol-reactive lipids that would undergo a covalent reaction with the Fab. Using this strategy, Fab loading could be reliably controlled from 1-50 Fabs per CKP-NLP and was found to be independent of CKP density. Surprisingly, Fab incorporation into CKP-NLPs led to a substantial improvement in NLP stability (half-life > 24 h) at 37 °C; also, there was no reduction in CKP activity in the Fab-CKP-NLP conjugates compared to CKP-NLPs. Altogether, our data demonstrate the potential of NLPs as a promising platform for the targeted or multidrug delivery of peptide-based drug candidates in combination with Fabs.

Functionalized Particles Designed for Targeted Delivery

Pure bioactive compounds alone can only be exceptionally administered in medical treatment. Usually, drugs are produced as various forms of active compounds and auxiliary substances, combinations assuring the desired healing functions. One of the important drug forms is represented by a combination of active substances and particle-shaped polymer in the nano- or micrometer size range. The review describes recent progress in this field balanced with basic information. After a brief introduction, the paper presents a concise overview of polymers used as components of nano- and microparticle drug carriers. Thereafter, progress in direct synthesis of polymer particles with functional groups is discussed. A section is devoted to formation of particles by self-assembly of homo- and copolymer-bearing functional groups. Special attention is focused on modification of the primary functional groups introduced during particle preparation, including introduction of ligands promoting anchorage of particles onto the chosen living cell types by interactions with specific receptors present in cell membranes. Particular attention is focused on progress in methods suitable for preparation of particles loaded with bioactive substances. The review ends with a brief discussion of the still not answered questions and unsolved problems.

Chemical Conjugation Strategies for the Development of Protein-Based Subunit Nanovaccines

The production of subunit nanovaccines relies heavily on the development of a vaccine delivery system that is safe and efficient at delivering antigens to the target site. Nanoparticles have been extensively investigated for vaccine delivery over the years, as they often possess self-adjuvanting properties. The conjugation of antigens to nanoparticles by covalent bonds ensures co-delivery of these components to the same subset of immune cells in order to trigger the desired immune responses. Herein, we review covalent conjugation strategies for grafting protein or peptide antigens onto other molecules or nanoparticles to obtain subunit nanovaccines. We also discuss the advantages of chemical conjugation in developing these vaccines.

Safety and Efficacy of Personalized Cancer Vaccines in Combination With Immune Checkpoint Inhibitors in Cancer Treatment

Cancer immunotherapy can induce sustained responses in patients with cancers in a broad range of tissues, however, these treatments require the optimized combined therapeutic strategies. Despite immune checkpoint inhibitors (ICIs) have lasting clinical benefit, researchers are trying to combine them with other treatment modalities, and among them the combination with personalized cancer vaccines is attractive. Neoantigens, arising from mutations in cancer cells, can elicit strong immune response without central tolerance and out-target effects, which is a truly personalized method. Growing studies show that the combination can elevate the antitumor efficacy with acceptable safety and minimal additional toxicity compared with single agent vaccine or ICI. Herein, we have searched these preclinical and clinical trials and summarized safety and efficacy of personalized cancer vaccines combined with ICIs in several malignancies. Meanwhile, we discuss the rationale of the combination and future challenges.

Preclinical models and technologies to advance nanovaccine development

The remarkable success of targeted immunotherapies is revolutionizing cancer treatment. However, tumor heterogeneity and low immunogenicity, in addition to several tumor-associated immunosuppression mechanisms are among the major factors that have precluded the success of cancer vaccines as targeted cancer immunotherapies. The exciting outcomes obtained in patients upon the injection of tumor-specific antigens and adjuvants intratumorally, reinvigorated interest in the use of nanotechnology to foster the delivery of vaccines to address cancer unmet needs. Thus, bridging nano-based vaccine platform development and predicted clinical outcomes the selection of the proper preclinical model will be fundamental. Preclinical models have revealed promising outcomes for cancer vaccines. However, only few cases were associated with clinical responses. This review addresses the major challenges related to the translation of cancer nano-based vaccines to the clinic, discussing the requirements for ex vivo and in vivo models of cancer to ensure the translation of preclinical success to patients.

Personalized combination nano-immunotherapy for robust induction and tumor infiltration of CD8+ T cells

Identification of tumor-specific mutations, called neoantigens, offers new exciting opportunities for personalized cancer immunotherapy. However, it remains challenging to achieve robust induction of neoantigen-specific T cells and drive their infiltration into the tumor microenvironment (TME). Here, we have developed a novel polyethyleneimine (PEI)-based personalized vaccine platform carrying neoantigen peptides and CpG adjuvants in a compact nanoparticle (NP) for their spatio-temporally concerted delivery. The NP vaccine significantly enhanced activation and antigen cross-presentation of dendritic cells, resulting in strong priming of neoantigen-specific CD8⁺ T cells with the frequency in the systemic circulation reaching as high as 23 ± 7% after a single subcutaneous administration. However, activated CD8⁺ T cells in circulation exhibited limited tumor infiltration, leading to poor anti-tumor efficacy. Notably, local administration of stimulator of interferon genes (STING) agonist promoted tumor infiltration of vaccine-primed CD8⁺ T cells, thereby overcoming one of the major challenges in achieving strong anti-tumor efficacy with cancer vaccination. The NP vaccination combined with STING agonist therapy eliminated tumors in murine models of MC-38 colon carcinoma and B16F10 melanoma and established long-term immunological memory. Our approach provides a novel therapeutic strategy based on combination nano-immunotherapy for personalized cancer immunotherapy.

Engineered Nanoparticles for Cancer Vaccination and Immunotherapy

The immune system has evolved over time to protect the host from foreign microorganisms. Activation of the immune system is predicated on a distinction between self and nonself. Unfortunately, cancer is characterized by genetic alterations in the host's cells, leading to uncontrolled cellular proliferation and evasion of immune surveillance. Cancer immunotherapy aims to educate the host's immune system to not only recognize but also attack and kill mutated cancer cells. While immune checkpoint blockers have been proven to be effective against multiple types of advanced cancer, the overall patient response rate still remains below 30%. Therefore, there is an urgent need to improve current cancer immunotherapies. In this Account, we present an overview of our recent progress on nanoparticle-based strategies for improving cancer vaccines and immunotherapies. We also present other complementary strategies to give a well-rounded snapshot of the field of combination cancer immunotherapy. The versatility and tunability of nanoparticles make them promising platforms for addressing individual challenges posed by various cancers. For example, nanoparticles can deliver cargo materials to specific cells, such as vaccines delivered to antigen-presenting cells for strong immune activation. Nanoparticles also allow for stimuli-responsive delivery of various therapeutics to cancer cells, thus forming the basis for combination cancer immunotherapy. Here, we focus on nanoparticle platforms engineered to deliver tumor antigens, whole tumor cells, and chemotherapeutic or phototherapeutic agents in a manner to effectively and safely trigger the host's immune system against tumor cells. For each work, we discuss the nanoparticle platform developed, synthesis chemistry, and in vivo applications. Nanovaccines offer a unique platform for codelivery of personalized tumor neoantigens and adjuvants and elicitation of robust immune responses against aggressive tumors. Nanovaccines either delivering whole tumor cell lysate or formed from tumor cell lysate may increase the repertoire of tumor antigens as immune targets while exploiting immunogenic cell death to prime antitumor immune responses. We also discuss how antigen- and whole tumor cell-based approaches may open the door for personalized cancer vaccination and immunotherapy. On the other hand, chemotherapy, phototherapy, and radiotherapy are more standardized cancer therapies, and nanoparticle-based approaches may promote their ability to initiate T cell activation against tumor cells and improve antitumor efficacy with minimal toxicity. Finally, building on the recent progress in nanoparticle-based cancer immunotherapy, the field should set the ultimate goal to be clinical translation and clinical efficacy. We will discuss regulatory, analytical, and manufacturing hurdles that should be addressed to expedite the clinical translation of nanomedicine-based cancer immunotherapy.

Cancer Immunotherapy via Targeting Cancer Stem Cells Using Vaccine Nanodiscs

Cancer stem cells (CSCs) proliferate extensively and drive tumor metastasis and recurrence. CSCs have been identified in over 20 cancer types to date, but it remains unknown how to target and eliminate CSCs in vivo. Aldehyde dehydrogenase (ALDH) is a marker that has been used extensively for isolating CSCs. Here we present a novel approach to target and reduce the frequency of ALDH^high CSCs by vaccination against ALDH. We have identified ALDH1-A1 and ALDH1-A3 epitopes from CSCs and developed synthetic high-density lipoprotein nanodiscs for vaccination against ALDH^high CSCs. Nanodiscs increased antigen trafficking to lymph nodes and generated robust ALDH-specific T cell responses. Nanodisc vaccination against ALDH^high CSCs combined with anti-PD-L1 therapy exerted potent antitumor efficacy and prolonged animal survival in multiple murine models. Overall, this is the first demonstration of a simple nanovaccine strategy against CSCs and may lead to new avenues for cancer immunotherapy against CSCs.

Lymph-directed immunotherapy - Harnessing endogenous lymphatic distribution pathways for enhanced therapeutic outcomes in cancer

The advent of immunotherapy has revolutionised the treatment of some cancers. Harnessing the immune system to improve tumour cell killing is now standard clinical practice and immunotherapy is the first line of defence for many cancers that historically, were difficult to treat. A unifying concept in cancer immunotherapy is the activation of the immune system to mount an attack on malignant cells, allowing the body to recognise, and in some cases, eliminate cancer. However, in spite of a significant proportion of patients that respond well to treatment, there remains a subset who are non-responders and a number of cancers that cannot be treated with these therapies. These limitations highlight the need for targeted delivery of immunomodulators to both tumours and the effector cells of the immune system, the latter being highly concentrated in the lymphatic system. In this context, macromolecular therapies may provide a significant advantage. Macromolecules are too large to easily access blood capillaries and instead typically exhibit preferential uptake via the lymphatic system. In contexts where immune cells are the therapeutic target, particularly in cancer therapy, this may be advantageous. In this review, we examine in brief the current immunotherapy approaches in cancer and how macromolecular and nanomedicine strategies may improve the therapeutic profiles of these drugs. We subsequently discuss how therapeutics directed either by parenteral or mucosal administration, can be taken up by the lymphatics thereby accessing a larger proportion of the body's immune cells. Finally, we detail drug delivery strategies that have been successfully employed to target the lymphatics.

Preferences of Type 1 Diabetic Patients on Devices for Islet Transplantation

Transplantation of pancreatic islets within a biomaterial device is currently under investigation in clinical trials for the treatment of patients with type 1 diabetes (T1D). Patients’ preferences on such implants could guide the designs of next-generation implantable devices; however, such information is not currently available. We surveyed the preferences of 482 patients with T1D on the size, shape, visibility, and transplantation site of islet containing implants. More than 83% of participants were willing to receive autologous stem cells, and there was no significant association between implant fabricated by one’s own stem cell with gender (χ² (1, n = 468) = 0.28; P = 0.6) or with age (χ² (4, n = 468) = 2.92; P = 0.6). Preferred location for islet transplantation within devices was under the skin (52.7%). 48.3% preferred microscopic disks, and 32.3% preferred a thin device (like a credit card). Moreover, 58.4% preferred the implant to be as small as possible, 25.4% did not care about visibility, and 16.2% preferred their implants not to be visible. Among female participants, 81% cared about the implant visibility, whereas this number was 64% for male respondents (χ² test (1, n = 468) = 16.34; P < 0.0001). 22% of those younger than 50 years of age and 30% of those older than 50 did not care about the visibility of implant (χ² test (4, n = 468) = 23.69; P < 0.0001). These results suggest that subcutaneous sites and micron-sized devices are preferred choices among patients with T1D who participated in our survey.

Chemical Strategies to Boost Cancer Vaccines

Personalized cancer vaccines (PCVs) are reinvigorating vaccine strategies in cancer immunotherapy. In contrast to adoptive T-cell therapy and checkpoint blockade, the PCV strategy modulates the innate and adaptive immune systems with broader activation to redeploy antitumor immunity with individualized tumor-specific antigens (neoantigens). Following a sequential scheme of tumor biopsy, mutation analysis, and epitope prediction, the administration of neoantigens with synthetic long peptide (SLP) or mRNA formulations dramatically improves the population and activity of antigen-specific CD4+ and CD8+ T cells. Despite the promising prospect of PCVs, there is still great potential for optimizing prevaccination procedures and vaccine potency. In particular, the arduous development of tumor-associated antigen (TAA)-based vaccines provides valuable experience and rational principles for augmenting vaccine potency which is expected to advance PCV through the design of adjuvants, delivery systems, and immunosuppressive tumor microenvironment (TME) reversion since current personalized vaccination simply admixes antigens with adjuvants. Considering the broader application of TAA-based vaccine design, these two strategies complement each other and can lead to both personalized and universal therapeutic methods. Chemical strategies provide vast opportunities for (1) exploring novel adjuvants, including synthetic molecules and materials with optimizable activity, (2) constructing efficient and precise delivery systems to avoid systemic diffusion, improve biosafety, target secondary lymphoid organs, and enhance antigen presentation, and (3) combining bioengineering methods to innovate improvements in conventional vaccination, "smartly" re-educate the TME, and modulate antitumor immunity. As chemical strategies have proven versatility, reliability, and universality in the design of T cell- and B cell-based antitumor vaccines, the union of such numerous chemical methods in vaccine construction is expected to provide new vigor and vitality in cancer treatment.

Robust anti-tumor T cell response with efficient intratumoral infiltration by nanodisc cancer immunotherapy

Potent anti-tumor T cell response and efficient intratumoral T cell infiltration are the major challenges for therapeutic cancer vaccines. To address these issues, a nano-vaccine system has been designed to promote anti-tumor T cell responses, and intratumoral infiltration was examined in various murine tumor models. Subcutaneous vaccination with nanodiscs carrying human papillomavirus (HPV)-16 E7 antigen elicits as high as ~32% E7-specific CD8 α + T cell responses in circulation, representing a 29-fold improvement over the soluble peptide vaccination. Importantly, nanodisc vaccination also promotes robust intratumoral T cell infiltration and eliminates HPV16 E6/E7-expressing TC-1 tumors at mucosal sites, including lungs, inner lip, and intravaginal tissues. In a benchmark study with a live Listeria vaccine combined with anti-PD-1 IgG, nanodiscs plus anti-PD-1 immune checkpoint blockade elicits comparable levels of T cell responses with anti-tumor efficacy. Furthermore, compared with Complete Freund's Adjuvant combined with tetanus toxoid, nanodisc vaccination in HLA-A02 mice generates >200-fold stronger IFN-γ+ T cell responses against a neoantigen from an HLA-A02 melanoma patient. Overall, these results show that the nanodisc system is a promising cancer vaccine platform for inducing anti-tumor T cell responses.

Synthetic High-density Lipoprotein Nanodiscs for Personalized Immunotherapy Against Gliomas

PURPOSE

Gliomas are brain tumors with dismal prognoses. The standard-of-care treatments for gliomas include surgical resection, radiation, and temozolomide administration; however, they have been ineffective in providing significant increases in median survival. Antigen-specific cancer vaccines and immune checkpoint blockade may provide promising immunotherapeutic approaches for gliomas.

EXPERIMENTAL DESIGN

We have developed immunotherapy delivery vehicles based on synthetic high-density lipoprotein (sHDL) loaded with CpG, a Toll-like receptor-9 agonist, and tumor-specific neoantigens to target gliomas and elicit immune-mediated tumor regression.

RESULTS

We demonstrate that vaccination with neoantigen peptide-sHDL/CpG cocktail in combination with anti-PD-L1 immune checkpoint blocker elicits robust neoantigen-specific T-cell responses against GL261 cells and eliminated established orthotopic GL261 glioma in 33% of mice. Mice remained tumor free upon tumor cell rechallenge in the contralateral hemisphere, indicating the development of immunologic memory. Moreover, in a genetically engineered murine model of orthotopic mutant IDH1 (mIDH1) glioma, sHDL vaccination with mIDH1 neoantigen eliminated glioma in 30% of animals and significantly extended the animal survival, demonstrating the versatility of our approach in multiple glioma models.

CONCLUSIONS

Overall, our strategy provides a general roadmap for combination immunotherapy against gliomas and other cancer types.

Rational Design of Antigen Incorporation Into Subunit Vaccine Biomaterials Can Enhance Antigen-Specific Immune Responses

Peptide subunit vaccines increase safety by reducing the risk of off-target responses and improving the specificity of the induced adaptive immune response. The immunogenicity of most soluble peptides, however, is often insufficient to produce robust and lasting immunity. Many biomaterials and delivery vehicles have been developed for peptide antigens to improve immune response while maintaining specificity. Peptide nanoclusters (PNC) are a subunit peptide vaccine material that has shown potential to increase immunogenicity of peptide antigens. PNC are comprised only of crosslinked peptide antigen and have been synthesized from several peptide antigens as small as 8 amino acids in length. However, as with many peptide vaccine biomaterials, synthesis requires adding residues to the peptide and/or engaging amino acids within the antigen epitope covalently to form a stable material. The impact of antigen modifications made to enable biomaterial incorporation or formation is rarely investigated, since the goal of most studies is to compare the soluble antigen with biomaterial form of antigen. This study investigates PNC as a platform vaccine biomaterial to evaluate how peptide modification and biomaterial formation with different crosslinking chemistries affect epitope-specific immune cell presentation and activation. Several types of PNC were synthesized by desolvation from the model peptide epitope SIINFEKL, which is derived from the immunogenic protein ovalbumin. SIINFEKL was altered to include extra residues on each end, strategically chosen to enable multiple conjugation chemistry options for incorporation into PNC. Several crosslinking methods were used to control which functional groups were used to stabilize the PNC, as well as the reducibility of the crosslinking. These variations were evaluated for immune responses and biodistribution following in vivo immunization. All modified antigen formulations still induced comparable immune responses when incorporated into PNC compared to unmodified soluble antigen alone. However, some crosslinking methods led to a significant increase in desirable immune responses while others did not, suggesting that not all PNC were processed the same. These results help guide future peptide vaccine biomaterial design, including PNC and a wide variety of conjugated and self-assembled peptide antigen materials, to maximize and tune the desired immune response.

Immunotherapy for gliomas: shedding light on progress in preclinical and clinical development

INTRODUCTION

Gliomas are infiltrating brain tumors associated with high morbidity and mortality. Current standard of care includes radiation, chemotherapy, and surgical resection. Today, survival rates for malignant glioma patients remain dismal and unchanged for decades. The glioma microenvironment is highly immunosuppressive and consequently this has motivated the development of immunotherapies for counteracting this condition, enabling the immune cells within the tumor microenvironment to react against this tumor.

AREAS COVERED

The authors discuss immunotherapeutic strategies for glioma in phase-I/II clinical trials and illuminate their mechanisms of action, limitations, and key challenges. They also examine promising approaches under preclinical development.

EXPERT OPINION

In the last decade there has been an expansion in immune-mediated anti-cancer therapies. In the glioma field, sophisticated strategies have been successfully implemented in preclinical models. Unfortunately, clinical trials have not yet yielded consistent results for glioma patients. This could be attributed to our limited understanding of the complex immune cell infiltration and its interaction with the tumor cells, the selected time for treatment, the combination with other therapies and the route of administration of the agent. Applying these modalities to treat malignant glioma is challenging, but many new alternatives are emerging to by-pass these hurdles.

Advancements in prophylactic and therapeutic nanovaccines

Vaccines activate suitable immune responses to fight against diseases but can possess limitations such as compromised efficacy and immunogenic responses, poor stability, and requirement of adherence to multiple doses. ‘Nanovaccines’ have been explored to elicit a strong immune response with the advantages of nano-sized range, high antigen loading, enhanced immunogenicity, controlled antigen presentation, more retention in lymph nodes and promote patient compliance by a lower frequency of dosing. Various types of nanoparticles with diverse pathogenic or foreign antigens can help to overcome immunotolerance and alleviate the need of booster doses as required with conventional vaccines. Nanovaccines have the potential to induce both cell-mediated and antibody-mediated immunity and can render long-lasting immunogenic memory. With such properties, nanovaccines have shown high potential for the prevention of infectious diseases such as acquired immunodeficiency syndrome (AIDS), malaria, tuberculosis, influenza, and cancer. Their therapeutic potential has also been explored in the treatment of cancer. The various kinds of nanomaterials used for vaccine development and their effects on immune system activation have been discussed with special relevance to their implications in various pathological conditions.

Statement of Significance

Interaction of nanoparticles with the immune system has opened multiple avenues to combat a variety of infectious and non-infectious pathological conditions. Limitations of conventional vaccines have paved the path for nanomedicine associated benefits with a hope of producing effective nanovaccines. This review highlights the role of different types of nanovaccines and the role of nanoparticles in modulating the immune response of vaccines. The applications of nanovaccines in infectious and non-infectious diseases like malaria, tuberculosis, AIDS, influenza, and cancers have been discussed. It will help the readers develop an understanding of mechanisms of immune activation by nanovaccines and design appropriate strategies for novel nanovaccines.

HIV-1 Envelope and MPER Antibody Structures in Lipid Assemblies

Structural and functional studies of HIV envelope glycoprotein (Env) as a transmembrane protein have long been complicated by challenges associated with inherent flexibility of the molecule and the membrane-embedded hydrophobic regions. Here, we present approaches for incorporating full-length, wild-type HIV-1 Env, as well as C-terminally truncated and stabilized versions, into lipid assemblies, providing a modular platform for Env structural studies by single particle electron microscopy. We reconstitute a full-length Env clone into a nanodisc, complex it with a membrane-proximal external region (MPER) targeting antibody 10E8, and structurally define the full quaternary epitope of 10E8 consisting of lipid, MPER, and ectodomain contacts. By aligning this and other Env-MPER antibody complex reconstructions with the lipid bilayer, we observe evidence of Env tilting as part of the neutralization mechanism for MPER-targeting antibodies. We also adapt the platform toward vaccine design purposes by introducing stabilizing mutations that allow purification of unliganded Env with a peptidisc scaffold.

Materials for Immunotherapy

Breakthroughs in materials engineering have accelerated the progress of immunotherapy in preclinical studies. The interplay of chemistry and materials has resulted in improved loading, targeting, and release of immunomodulatory agents. An overview of the materials that are used to enable or improve the success of immunotherapies in preclinical studies is presented, from immunosuppressive to proinflammatory strategies, with particular emphasis on technologies poised for clinical translation. The materials are organized based on their characteristic length scale, whereby the enabling feature of each technology is organized by the structure of that material. For example, the mechanisms by which i) nanoscale materials can improve targeting and infiltration of immunomodulatory payloads into tissues and cells, ii) microscale materials can facilitate cell-mediated transport and serve as artificial antigen-presenting cells, and iii) macroscale materials can form the basis of artificial microenvironments to promote cell infiltration and reprogramming are discussed. As a step toward establishing a set of design rules for future immunotherapies, materials that intrinsically activate or suppress the immune system are reviewed. Finally, a brief outlook on the trajectory of these systems and how they may be improved to address unsolved challenges in cancer, infectious diseases, and autoimmunity is presented.