Biomaterials for vaccine-based cancer immunotherapy

Localized delivery of immunotherapeutics: A rising trend in the field

Immunotherapy is becoming a new standard of care for multiple cancers, while several limitations are impending its further clinical success. Immunotherapeutic agents often have inappropriate pharmacokinetics on their own and/or exhibit limited specificity to tumor cells, leading to severe immuno-related adverse effects and limited efficacy. Suitable formulating strategies that confer prolonged contact with or efficient proliferation in tumors while reducing exposure to normal tissues are highly worthy to explore. With the assistance of biomaterial carriers, targeted therapy can be achieved artificially by implanting or injecting drug depots into desired sites, about which the wisdoms in literature have been rich. The relevant results have suggested a "local but systemic" effect, that is, local replenishment of immune modulators achieves a high treatment efficacy that also governs distant metastases, thereby building another rationale for localized delivery. Particularly, implantable scaffolds have been further engineered to recruit disseminated tumor cells with an efficiency high enough to reduce tumor burdens at typical metastatic organs, and simultaneously provide diagnostic signals. This review introduces recent advances in this emerging area along with a perspective on the opportunities and challenges in the way to clinical application.

Nanovaccines silencing IL-10 production at priming phase for boosting immune responses to melanoma

Despite the significant efforts in developing cancer vaccines, there are still numerous challenges that need to be addressed to ensure their clinical efficacy. Herein, a lymphatic dendritic cell (DC)-targeted artificial nanovaccine mimicking tumor cell membrane (ATM-NV) is developed to boost effector immune response and control immunosuppression simultaneously. The NVs are formulated with lipids, tumor cell membrane proteins, imiquimod (IMQ), and IL-10 siRNA. IL-10 siRNA is incorporated to inhibit the secretion of IL-10, an immunosuppressive cytokine, of maturated DCs upon IMQ. To enhance the DC targeting ability, the nanovaccine surface was non-covalently conjugated with the anti-CD205 antibody. The IMQ and IL-10 siRNA co-loaded, CD205 receptor-targeted artificial tumor membrane NVs (IMQ/siR@ATM-NVs) efficiently migrate to the tumor-draining lymph node and target DCs. Furthermore, immunization with IMQ/siR@ATM-NVs reduces the production of IL-10 and increases T_h1-driven antitumor immunity resulted in a great tumor inhibition efficacy. Our results suggest a potential strategy to promote the vaccination's antitumor efficacy by blocking the intrinsic negative regulators in DCs.

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.

Pancreatic Cancer and Immunotherapy: A Clinical Overview

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease with high mortality. The vast majority of patients present with unresectable, advanced stage disease, for whom standard of care chemo(radio)therapy may improve survival by several months. Immunotherapy has led to a fundamental shift in the treatment of several advanced cancers. However, its efficacy in PDAC in terms of clinical benefit is limited, possibly owing to the immunosuppressive, inaccessible tumor microenvironment. Still, various immunotherapies have demonstrated the capacity to initiate local and systemic immune responses, suggesting an immune potentiating effect. In this review, we address PDAC's immunosuppressive tumor microenvironment and immune evasion methods and discuss a wide range of immunotherapies, including immunomodulators (i.e., immune checkpoint inhibitors, immune stimulatory agonists, cytokines and adjuvants), oncolytic viruses, adoptive cell therapies (i.e., T cells and natural killer cells) and cancer vaccines. We provide a general introduction to their working mechanism as well as evidence of their clinical efficacy and immune potentiating abilities in PDAC. The key to successful implementation of immunotherapy in this disease may rely on exploitation of synergistic effects between treatment combinations. Accordingly, future treatment approaches should aim to incorporate diverse and novel immunotherapeutic strategies coupled with cytotoxic drugs and/or local ablative treatment, targeting a wide array of tumor-induced immune escape mechanisms.

Hydrogel-By-Design: Smart Delivery System for Cancer Immunotherapy

Immunotherapy has emerged as a promising strategy for cancer treatment, in which durable immune responses were generated in patients with malignant tumors. In the past decade, biomaterials have played vital roles as smart drug delivery systems for cancer immunotherapy to achieve both enhanced therapeutic benefits and reduced side effects. Hydrogels as one of the most biocompatible and versatile biomaterials have been widely applied in localized drug delivery systems due to their unique properties, such as loadable, implantable, injectable, degradable and stimulus responsible. Herein, we have briefly summarized the recent advances on hydrogel-by-design delivery systems including the design of hydrogels and their applications for delivering of immunomodulatory molecules (e.g., cytokine, adjuvant, checkpoint inhibitor, antigen), immune cells and environmental regulatory substances in cancer immunotherapy. We have also discussed the challenges and future perspectives of hydrogels in the development of cancer immunotherapy for precision medicine at the end.

Recent advances in regenerative medicine strategies for cancer treatment

Cancer stands as one of the most leading causes of death worldwide, while one of the most significant challenges in treating it is revealing novel alternatives to predict, diagnose, and eradicate tumor cell growth. Although various methods, such as surgery, chemotherapy, and radiation therapy, are used today to treat cancer, its mortality rate is still high due to the numerous shortcomings of each approach. Regenerative medicine field, including tissue engineering, cell therapy, gene therapy, participate in cancer treatment and development of cancer models to improve the understanding of cancer biology. The final intention is to convey fundamental and laboratory research to effective clinical treatments, from the bench to the bedside. Proper interpretation of research attempts helps to lessen the burden of treatment and illness for patients. The purpose of this review is to investigate the role of regenerative medicine in accelerating and improving cancer treatment. This study examines the capabilities of regenerative medicine in providing novel cancer treatments and the effectiveness of these treatments to clarify this path as much as possible and promote advanced future research in this field.

Microfluidic formulation of nanoparticles for biomedical applications

Nanomedicine has made significant advances in clinical applications since the late-20th century, in part due to its distinct advantages in biocompatibility, potency, and novel therapeutic applications. Many nanoparticle (NP) therapies have been approved for clinical use, including as imaging agents or as platforms for drug delivery and gene therapy. However, there are remaining challenges that hinder translation, such as non-scalable production methods and the inefficiency of current NP formulations in delivering their cargo to their target. To address challenges with existing formulation methods that have batch-to-batch variability and produce particles with high dispersity, microfluidics-devices that manipulate fluids on a micrometer scale-have demonstrated enormous potential to generate reproducible NP formulations for therapeutic, diagnostic, and preventative applications. Microfluidic-generated NP formulations have been shown to have enhanced properties for biomedical applications by formulating NPs with more controlled physical properties than is possible with bulk techniques-such as size, size distribution, and loading efficiency. In this review, we highlight advances in microfluidic technologies for the formulation of NPs, with an emphasis on lipid-based NPs, polymeric NPs, and inorganic NPs. We provide a summary of microfluidic devices used for NP formulation with their advantages and respective challenges. Additionally, we provide our analysis for future outlooks in the field of NP formulation and microfluidics, with emerging topics of production scale-independent formulations through device parallelization and multi-step reactions within droplets.

Biomaterials and nanomaterials for sustained release vaccine delivery

Vaccines are considered one of the most significant medical advancements in human history, as they have prevented hundreds of millions of deaths since their discovery; however, modern travel permits disease spread at unprecedented rates, and vaccine shortcomings like thermal sensitivity and required booster shots have been made evident by the COVID-19 pandemic. Approaches to overcoming these issues appear promising via the integration of vaccine technology with biomaterials, which offer sustained-release properties and preserve proteins, prevent conformational changes, and enable storage at room temperature. Sustained release and thermal stabilization of therapeutic biomacromolecules is an emerging area that integrates material science, chemistry, immunology, nanotechnology, and pathology to investigate different biocompatible materials. Biomaterials, including natural sugar polymers, synthetic polyesters produced from biologically derived monomers, hydrogel blends, protein-polymer blends, and metal-organic frameworks, have emerged as early players in the field. This overview will focus on significant advances of sustained release biomaterial in the context of vaccines against infectious disease and the progress made towards thermally stable "single-shot" formulations. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease.

Mimicking Pathogens to Augment the Potency of Liposomal Cancer Vaccines

Liposomes have emerged as interesting vehicles in cancer vaccination strategies as their composition enables the inclusion of both hydrophilic and hydrophobic antigens and adjuvants. In addition, liposomes can be decorated with targeting moieties to further resemble pathogenic particles that allow for better engagement with the immune system. However, so far liposomal cancer vaccines have not yet reached their full potential in the clinic. In this review, we summarize recent preclinical studies on liposomal cancer vaccines. We describe the basic ingredients for liposomal cancer vaccines, tumor antigens, and adjuvants, and how their combined inclusion together with targeting moieties potentially derived from pathogens can enhance vaccine immunogenicity. We discuss newly identified antigen-presenting cells in humans and mice that pose as promising targets for cancer vaccines. The lessons learned from these preclinical studies can be applied to enhance the efficacy of liposomal cancer vaccination in the clinic.

Using nanoparticles for in situ vaccination against cancer: mechanisms and immunotherapy benefits

Immunotherapy to treat cancer is now an established clinical approach. Immunotherapy can be applied systemically, as done with checkpoint blockade antibodies, but it can also be injected directly into identified tumors, in a strategy of in situ vaccination (ISV). ISV is designed to stimulate a strong local antitumor immune response involving both innate and adaptive immune cells, and through this generate a systemic antitumor immune response against metastatic tumors. A variety of ISVs have been utilized to generate an immunostimulatory tumor microenvironment (TME). These include attenuated microorganisms, recombinant proteins, small molecules, physical disruptors of TME (alternating magnetic and focused ultrasound heating, photothermal therapy, and radiotherapy), and more recently nanoparticles (NPs). NPs are attractive and unique since they can load multiple drugs or other reagents to influence immune and cancer cell functions in the TME, affording a unique opportunity to stimulate antitumor immunity. Here, we describe the NP-ISV therapeutic mechanisms, review chemically synthesized NPs (i.e., liposomes, polymeric, chitosan-based, inorganic NPs, etc.), biologically derived NPs (virus and bacteria-based NPs), and energy-activated NP-ISVs in the context of their use as local ISV. Data suggests that NP-ISVs can enhance outcomes of immunotherapeutic regimens including those utilizing tumor hyperthermia and checkpoint blockade therapies.

Design, synthesis and immunological evaluation of self-assembled antigenic peptides from dual-antigen targets: a broad-spectrum candidate for an effective antibreast cancer therapy

Background

Considering the narrow immune response spectrum of a single epitope, and the nanoparticles (NPs) as a novel adjuvant can achieve efficient delivery of antigenic peptides safely, a nano-system (denoted as DSPE-PEG-Man@EM-NPs) based on cathepsin B-responsive antigenic peptides was designed and synthesized.

Methods

Highly affinitive antigenic peptides were delivered by self-assembled NPs, and targeted erythrocyte membranes acted as a peptide carrier to improve antigenic peptides presentation and to strengthen cytotoxic T-cells reaction. Cathepsin B coupling could release antigenic peptides rapidly in dendritic cells.

Results

Evaluations showed that DSPE-PEG-Man@EM-NPs had obvious inhibitory effects towards both MCF-7 and MDA-MB-231 human breast cancer cell lines.

Conclusion

Overall, this strategy provides a novel strategy for boosting cytotoxic T lymphocytes response, thereby expanding the adaptation range of tumor antigenic peptides and improving the therapeutic effect of tumor immunotherapy with nanomedicine.

A novel self-assembled epitope peptide nanoemulsion vaccine targeting nasal mucosal epithelial cell for reinvigorating CD8+ T cell immune activity and inhibiting tumor progression

Epitope peptides are not suitable for nasal administration immunity due to their poor immunogenicity and low delivery efficiency. Here, we reported an intranasal self-assembled nanovaccine (I-OVA NE), which was loaded with the peptides IKVAV-OVA_257-264 (I-OVA), a laminin peptide (Ile-Lys-Val-ala-Val, IKVAV) and OVA_257-264 epitope conjugated peptide. This nanovaccine with I-OVA at a concentration of 4 mg/mL showed the average particle size of 30.37 ± 2.49 nm, zeta potential of -16.67 ± 1.76 mV, and encapsulation rate of 84.07 ± 7.59%. Moreover, the mucin did not alter its stability (size, PdI and zeta potential). And it also had no obvious acute pathological changes neither in the nasal mucosa nor lung tissues after nasal administration. Meanwhile, the antigen uptake of I-OVA NE was promoted, and the nasal residence time was also prolonged in vivo. Besides, the uptake rate of this nanovaccine was obviously higher than that of free I-OVA (P < 0.001) after blocking by the integrin antibody, suggesting that the binding of IKVAV to integrin is involved in the epitope peptide uptake. Importantly, this nanovaccine enhanced peptide-specific CD8⁺T cells exhibiting OVA_257-264-specific CTL activity and Th1 immune response, leading to the induction of the protective immunity in E.G7-OVA tumor-bearing mice. Overall, these data indicate that I-OVA NE can be an applicable strategy of tumor vaccine development.

Biomaterial-based approaches to engineering immune tolerance

The development of biomaterial-based therapeutics to induce immune tolerance holds great promise for the treatment of autoimmune diseases, allergy, and graft rejection in transplantation. Historical approaches to treat these immunological challenges have primarily relied on systemic delivery of broadly-acting immunosuppressive agents that confer undesirable, off-target effects. The evolution and expansion of biomaterial platforms has proven to be a powerful tool in engineering immunotherapeutics and enabled a great diversity of novel and targeted approaches in engineering immune tolerance, with the potential to eliminate side effects associated with systemic, non-specific immunosuppressive approaches. In this review, we summarize the technological advances within three broad biomaterials-based strategies to engineering immune tolerance: nonspecific tolerogenic agent delivery, antigen-specific tolerogenic therapy, and the emergent area of tolerogenic cell therapy.

Prophylactic Cancer Vaccines Engineered to Elicit Specific Adaptive Immune Response

Vaccines have been used to prevent and eradicate different diseases for over 200 years, and new vaccine technologies have the potential to prevent many common illnesses. Cancer, despite many advances in therapeutics, is still the second leading causes of death in the United States. Prophylactic, or preventative, cancer vaccines have the potential to reduce cancer prevalence by initiating a specific immune response that will target cancer before it can develop. Cancer vaccines can include many different components, such as peptides and carbohydrates, and be fabricated for delivery using a variety of means including through incorporation of stabilizing chemicals like polyethylene glycol (PEG) and pan-DR helper T-lymphocyte epitope (PADRE), fusion with antigen-presenting cells (APCs), microneedle patches, and liposomal encapsulation. There are currently five cancer vaccines used in the clinic, protecting against either human papillomavirus (HPV) or hepatitis B virus (HBV), and preventing several different types of cancer including cervical and oral cancer. Prophylactic cancer vaccines can promote three different types of adaptive responses: humoral (B cell, or antibody-mediated), cellular (T cell) or a combination of the two types. Each vaccine has its advantages and challenges at eliciting an adaptive immune response, but these prophylactic cancer vaccines in development have the potential to prevent or delay tumor development, and reduce the incidence of many common cancers.

Enhancing Cancer Immunotherapy Treatment Goals by Using Nanoparticle Delivery System

Recently, there has been an incredible increase in research about the abnormal growth of cells (neoplasm), focusing on the management, treatment and preventing reoccurrence. It has been understood that the natural defense system, composed of a variety of immune defensive cells, does not just limit its function in eliminating neoplastic cells, but also controls the growth and spread of tumor cells of different kinds to other parts of the body. Cancer immunotherapy, is a cancer treatment plan that educates the body’s defensive system to forestall, control, and eliminate tumor cells. The effectiveness of immunotherapy is achieved, to its highest efficacy, by the use of nanoparticles (NPs) for precise and timely delivery of immunotherapies to specific targeted neoplasms, with less or no harm to the healthy cells. Immunotherapies have been affirmed in clinical trials as a cancer regimen for various types of cancers, the side effects resulting from imprecise and non-targeted conveyance is well managed with the use of nanoparticles. Nonetheless, we will concentrate on enhancing cancer immunotherapy approaches by the use of nanoparticles for the productivity of antitumor immunity. Nanoparticles will be presented and utilized as an objective immunotherapy delivery system for high exactness and are thus a promising methodology for cancer treatment.

Self-assembled mRNA vaccines

mRNA vaccines have evolved from being a mere curiosity to emerging as COVID-19 vaccine front-runners. Recent advancements in the field of RNA technology, vaccinology, and nanotechnology have generated interest in delivering safe and effective mRNA therapeutics. In this review, we discuss design and self-assembly of mRNA vaccines. Self-assembly, a spontaneous organization of individual molecules, allows for design of nanoparticles with customizable properties. We highlight the materials commonly utilized to deliver mRNA, their physicochemical characteristics, and other relevant considerations, such as mRNA optimization, routes of administration, cellular fate, and immune activation, that are important for successful mRNA vaccination. We also examine the COVID-19 mRNA vaccines currently in clinical trials. mRNA vaccines are ready for the clinic, showing tremendous promise in the COVID-19 vaccine race, and have pushed the boundaries of gene therapy.

Biomaterials-based formulations and surfaces to combat viral infectious diseases

Rapidly growing viral infections are potent risks to public health worldwide. Accessible virus-specific antiviral vaccines and drugs are therapeutically inert to emerging viruses, such as Zika, Ebola, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Therefore, discovering ways to prevent and control viral infections is among the foremost medical challenge of our time. Recently, innovative technologies are emerging that involve the development of new biomaterial-based formulations and surfaces endowed with broad-spectrum antiviral properties. Here, we review emerging biomaterials technologies for controlling viral infections. Relevant advances in biomaterials employed with nanotechnology to inactivate viruses or to inhibit virus replication and further their translation in safe and effective antiviral formulations in clinical trials are discussed. We have included antiviral approaches based on both organic and inorganic nanoparticles (NPs), which offer many advantages over molecular medicine. An insight into the development of immunomodulatory scaffolds in designing new platforms for personalized vaccines is also considered. Substantial research on natural products and herbal medicines and their potential in novel antiviral drugs are discussed. Furthermore, to control contagious viral infections, i.e., to reduce the viral load on surfaces, current strategies focusing on biomimetic anti-adhesive surfaces through nanostructured topography and hydrophobic surface modification techniques are introduced. Biomaterial surfaces functionalized with antimicrobial polymers and nanoparticles against viral infections are also discussed. We recognize the importance of research on antiviral biomaterials and present potential strategies for future directions in applying these biomaterial-based approaches to control viral infections and SARS-CoV-2.

Delivery technologies for in utero gene therapy

Advances in prenatal imaging, molecular diagnostic tools, and genetic screening have unlocked the possibility to treat congenital diseases in utero prior to the onset of clinical symptoms. While fetal surgery and in utero stem cell transplantation can be harnessed to treat specific structural birth defects and congenital hematological disorders, respectively, in utero gene therapy allows for phenotype correction of a wide range of genetic disorders within the womb. However, key challenges to realizing the broad potential of in utero gene therapy are biocompatibility and efficiency of intracellular delivery of transgenes. In this review, we outline the unique considerations to delivery of in utero gene therapy components and highlight advances in viral and non-viral delivery platforms that meet these challenges. We also discuss specialized delivery technologies for in utero gene editing and provide future directions to engineer novel delivery modalities for clinical translation of this promising therapeutic approach.

A dual-modal PET/near infrared fluorescent nanotag for long-term immune cell tracking

Adoptive cell transfer of targeted chimeric antigen receptor (CAR) T cells has emerged as a highly promising cancer therapy. The pharmacodynamic action or CAR T cells is closely related to their pharmacokinetic profile; because of this as well as the risk of non-specific action, it is important to monitor their biodistribution and fate following infusion. To this end, we developed a dual-modal PET/near infrared fluorescent (NIRF) nanoparticle-based imaging agent for non-genomic labeling of human CAR T cells. Since the PET/NIRF nanoparticles did not affect cell viability or cytotoxic functionality and enabled long-term whole-body CAR T cell tracking using PET and NIRF in an ovarian peritoneal carcinomatosis model, this platform is a viable imaging technology to be applied in other cancer models.

Microneedles for painless transdermal immunotherapeutic applications

Immunotherapy has recently garnered plenty of attention to improve the clinical outcomes in the treatment of various diseases. However, owing to the dynamic nature of the immune system, this approach has often been challenged by concerns regarding the lack of adequate long-term responses in patients. The development of microneedles (MNs) has resulted in the improvement and expansion of immuno-reprogramming strategies due to the housing of high accumulation of dendritic cells, macrophages, lymphocytes, and mast cells in the dermis layer of the skin. In addition, MNs possess many outstanding properties, such as the ability for the painless traverse of the stratum corneum, minimal invasiveness, facile fabrication, excellent biocompatibility, convenient administration, and bypassing the first pass metabolism that allows direct translocation of therapeutics into the systematic circulation. These advantages make MNs excellent candidates for the delivery of immunological biomolecules to the dermal antigen-presenting cells in the skin with the aim of vaccinating or treating different diseases, such as cancer and autoimmune disorders, with minimal invasiveness and side effects. This review discusses the recent advances in engineered MNs and tackles limitations relevant to traditional immunotherapy of various hard-to-treat diseases.

Bioprinting for combating infectious diseases

Infectious diseases have the ability to impact health on a global scale, as is being demonstrated by the current coronavirus disease 2019 (COVID-19) pandemic. The strenuous circumstances related to this global health crisis have been highlighting the challenges faced by the biomedical field in combating infectious diseases. Notably, printing technologies have advanced rapidly over the last decades, allowing for the incorporation of living cells in the printing process (or bioprinting) to create constructs that are able to serve as in vitro tissue or virus-disease models in combating infectious diseases. This paper describes applications of bioprinting in addressing the challenges faced in combating infectious diseases, with a specific focus on in vitro modelling and on development of therapeutic agents and vaccines. Integration of these technologies may allow for a more efficient and effective response to current and future pandemics.

BaBao Dan Suppresses Tumor Growth of Pancreatic Cancer Through Modulating Transcriptional Reprogramming of Cancer-Related Genes

Background and Aims

Pancreatic ductal adenocarcinoma (PDAC) is one of refractory malignancies without efficient therapeutics. Babao Dan (BBD) was partially effective to suppress tumor growth of PDAC in clinical practice. However, the molecular mechanisms were unclear.

Methods

We established PDAC mice models and treated them with BBD through intragastric administration. Treatment and control groups were then subjected to high-throughput RNA sequencing. We presented the transcriptional changes upon BBD treatment by using computational analysis comparing BBD treatment and control groups. Functional enrichment analysis was employed to investigate the biological processes or pathways that BBD modulates.

Results

BBD treatment showed strong suppression on tumor growth of PDAC, even stronger than Gemcitabine. Through differential analysis comparing BBD treatment and control groups, we identified 638 up-regulated and 259 down-regulated genes in the BBD treatment group. BBD was found to activate tumor suppressor genes, such as MTUS1, PDGFB, SOD3, and UCHL1. Furthermore, we revealed that BBD treatment inhibited cancer-related pathways and elevated activities of metabolism-related processes. The BBD-modulated metabolic genes were further showed to be associated with patient survival in an independent cohort with pancreatic cancer.

Conclusion

BBD repressed the tumor growth of PDAC. BBD treatment modulated expression of cancer-related genes in PDAC. BBD suppressed cancer-related pathways and activated metabolic processes in PDAC. Our study suggests BBD treatment as potential effective therapeutics for patients with pancreatic cancer.

Immunostimulatory biomaterials to boost tumor immunogenicity

Cancer immunotherapy is exhibiting great promise as a new therapeutic modality for cancer treatment. However, immunotherapies are limited by the inability of some tumors to provoke an immune response. These tumors with a 'cold' immunological phenotype are characterized by low numbers of tumor-infiltrating lymphocytes, high numbers of immunosuppressive leukocytes (e.g. regulatory T cells, tumor-associated macrophages), and high production of immune-dampening signals (e.g. IL-10, TGF-β, IDO-1). Strategies to boost the aptitude of tumors to initiate an immune response (i.e. boost tumor immunogenicity) will turn 'cold' tumors 'hot' and augment the anti-tumor efficacy of current immunotherapies. Approaches to boost tumor immunogenicity already show promise; however, multifaceted delivery and immunobiology challenges exist. For instance, systemic delivery of many immune-stimulating agents causes off-target toxicity and/or the development of autoimmunity, limiting the administrable dose below the threshold needed to achieve efficacy. Moreover, once administered in vivo, molecules such as the nucleic acid-based agonists for many pattern recognition receptors are either rapidly cleared or degraded, and don't efficiently traffic to the intracellular compartments where the receptors are located. Thus, these nucleic acid-based drugs are ineffective without a delivery system. Biomaterials-based approaches aim to enhance current strategies to boost tumor immunogenicity, enable novel strategies, and spare dose-limiting toxicities. Here, we review recent progress to improve cancer immunotherapies by boosting immunogenicity within tumors using immunostimulatory biomaterials.

Recombination Monophosphoryl Lipid A-Derived Vacosome for the Development of Preventive Cancer Vaccines

Recently, there has been an increasing interest for utilizing the host immune system to fight against cancer. Moreover, cancer vaccines, which can stimulate the host immune system to respond to cancer in the long term, are being investigated as a promising approach to induce tumor-specific immunity. In this work, we prepared an effective cancer vaccine (denoted as "vacosome") by reconstructing the cancer cell membrane, monophosphoryl lipid A as a toll-like receptor 4 agonist, and egg phosphatidylcholine. The vacosome triggered and enhanced bone marrow dendritic cell maturation as well as stimulated the antitumor response against breast cancer 4T1 cells in vitro. Furthermore, an immune memory was established in BALB/c mice after three-time preimmunization with the vacosome. After that, the immunized mice showed inhibited tumor growth and prolonged survival period (longer than 50 days). Overall, our results demonstrate that the vacosome can be a potential candidate for clinical translation as a cancer vaccine.

Immunological Evaluation of Co-Assembling a Lipidated Peptide Antigen and Lipophilic Adjuvants: Self-Adjuvanting Anti-Breast-Cancer Vaccine Candidates

Co-assembling vaccines composed of a lipidated HER2-derived antigenic CH401 peptide and either a lipophilic adjuvant, Pam₃ CSK₄ , α-GalCer, or lipid A 506, were evaluated as breast cancer vaccine candidates. This vaccine design was aimed to inherit both antigen multivalency and antigen-specific immunostimulation properties, observed in reported self-adjuvanting vaccine candidates, by using self-assembly and adjuvant-conjugated antigens. Under vaccination concentrations, respective lipophilic adjuvants underwent co-assembly with lipidated CH401, which boosted the anti-CH401 IgG and IgM production. In particular, α-GalCer was responsible for the most significant immune activation. Therefore, the newly developed vaccine design enabled the optimization of adjuvants against the antigenic CH401 peptide in a simple preparatory manner. Overall, the co-assembling vaccine design opens the door for efficient and practical self-adjuvanting vaccine development.

Engineering nanoparticulate vaccines for enhancing antigen cross-presentation

Efficient cross-presentation is pivotal for vaccination against cancer and infection by intracellular virus and bacteria. Recently, various types of nanoparticle vaccines have been developed and investigated for efficiently and specifically improving cross-presentation and CD8⁺ T cell priming. In this review, we will summarize the known intracellular pathways involved in cross-presentation, and focus on several nanoparticle strategies that have been reported for enhancing cross-presentation, including designing multifunctional nano-vaccines for increasing endosomal escape, designing nano-vaccines that can target lymph nodes to improve antigen uptake by lymph node resident CD8α⁺ dendritic cells, and co-delivering immune modulators for upregulating cross-presentation related intracellular components. We will also briefly discuss the future prospects of cross-presentation based nano-vaccine strategy for curing diseases.

Co-delivery of antigen and dual adjuvants by aluminum hydroxide nanoparticles for enhanced immune responses

Adjuvants that contain pathogen-associated molecular patterns (PAMPs) can enhance vaccination efficacy by binding to pattern recognition receptors (PRRs), thereby stimulating immune responses. Particularly effective may be the combination of multiple PAMPs that activate different PRRs, which occurs with natural pathogens. Here we hypothesized the enhanced effects would occur in two adjuvants that stimulate different PRRs: CpG oligodeoxynucleotide (CpG-ODN), which is Toll-like receptor 9 agonist; and 5'-triphosphate, short, double-stranded RNA (3pRNA), which activates retinoic acid-inducible gene I (RIG-I). The model antigen ovalbumin (OVA) was loaded and adjuvants were surface-adsorbed to aluminum hydroxide nanoparticles (hereafter NP-3pRNA-CpG) by electrostatic interaction with an average size of 120 nm and a negative surface charge for targeting lymph nodes. These nanoparticles were efficiently internalized by antigen-presenting cells (APCs) in the lymph nodes, and the resulting APC activation and antigen cross-presentation generated strong humoral immunity and cytotoxic T lymphocyte responses and IFN-γ secretion. NP-3pRNA-CpG significantly suppressed B16-OVA tumor growth and prolonged survival of tumor-bearing mice in therapeutic and prophylactic models, illustrating the enhanced effects of CpG-ODN and 3pRNA. Our study highlights the potential of combining multiple adjuvants for effective vaccine design.

Magnetic nanoparticles coated with polyphenols for spatio-temporally controlled cancer photothermal/immunotherapy

As the combination of photothermal therapy (PTT) with immunotherapy provides an effective strategy in cancer treatment, a magnetic nanoparticle delivery system was constructed to load indocyanine green (ICG) and immunostimulator R837 hydrochloride (R837) for spatio-temporally PTT/immunotherapy synergism in cancer. This delivery system is composed of Fe₃O₄ magnetic nanoparticles (MPs) as the core to load ICG and polyethylene glycol polyphenols (DPA-PEG) as the coating layer to load R837, which formed R837 loaded polyphenols coating ICG loaded magnetic nanoparticles (MIRDs). After intravenous injection, the formed MIRDs resulted in long circulation, magnetic resonance imaging (MRI) guides, and magnetic targeting. Once targeting to the tumor, the MIRDs with the near-infrared (NIR) irradiation caused tumor ablation and resulted in tumor-associated antigens releasing to induce the body's immunological response, which was markedly improved it to attack the tumors with the R837 releasing from the outer DPA-PEG. In this case, the synergism of the PTT and immunotherapy inhibited tumor growth, metastasis and recurrence, which resulted in potent anticancer therapeutic effects with few side effect.

Hexahistidine-Metal Assemblies: A Facile and Effective Codelivery System of Subunit Vaccines for Potent Humoral and Cellular Immune Responses

Fully effective vaccines must induce both potent humoral and cellular immunities. Nanoparticles coencapsulating antigens and adjuvants have shown promising advantages as subunit vaccines in many aspects. However, the low loading efficiency and complicated synthesis process of these nanomaterials need to be improved. Here, we utilized hexahistidine (His₆)-metal assembly (HmA) particles as carriers to codeliver ovalbumin peptides and cytosine-phosphate-guanine oligodeoxynucleotides (CpG ODNs). We found that antigen/adjuvant-carrying HmA can efficiently enter into antigen-presenting cells and help the antigens escape from lysosomes to induce the maturation of these cells in vitro, characterized by increasing expression levels of costimulatory molecules and cytokines. More importantly, the vaccines with high biocompatibility can elicit strong humoral and cellular immunities by improving secretion of specific antibodies and cytokines, enhancing activation of DCs and T cells in vivo. Our results suggest that HmA provides a new approach for subunit vaccines by codelivery of antigens and adjuvants.

Intranasal delivery of cationic liposome-protamine complex mRNA vaccine elicits effective anti-tumor immunity

Immunization with synthetic mRNA encoding tumor-associated antigens is an emerging vaccine strategy for the treatment of cancer. In order to prevent mRNA degradation, promote antigen-presenting cells antigen presentation, and induce an anti-tumor immune response, we investigated the nasal administration of mRNA vaccines with positively charged protamine to concentrate mRNA, form a stable polycation-mRNA complex, and encapsulate the complex with DOTAP/Chol/DSPE-PEG cationic liposomes. Cationic liposome/protamine complex (LPC) showed significantly greater efficiency in uptake of vaccine particles in vitro and stronger capacities to stimulate dendritic cell maturation, which further induced a potent anti-tumor immune response. Intranasal immunization of mice with cationic LPC containing mRNA encoding cytokeratin 19 provoked a strong cellular immune response and slowed tumor growth in an aggressive Lewis lung cancer model. The results of this study provide evidence that cationic LPC can be used as a safe and effective adjuvant and this mRNA formulation provides a basis for anti-cancer vaccination of humans.

Nanotherapeutic systems for delivering cancer vaccines: recent advances

With an increase in the global burden of cancer-related deaths, the quest for developing new therapeutic solutions has taken momentum. In this regard, the idea of using cancer vaccines came to existence approximately 30 years ago, where gene therapy interventions have shown significant improvement in the therapeutic outcomes against several types of cancers. Cancer vaccines usually encounter a number of challenges with limited targeting ability to the tumors. Nanocarriers have been studied as a technological innovation for tumor targeting of gene therapeutics. This article provides a critical insight into the recent progress made in nanotherapeutic strategies for genetic vaccine delivery for treatment against various types of cancers. Moreover, the article intends to provide a summary of the research work being done on this topic.

Personalized neoantigen vaccines: a glimmer of hope for glioblastoma

INTRODUCTION

Glioblastoma multiforme (GBM) is the most prevalent primary brain tumor. In spite of the rigorous multimodal treatment involving surgery and radiochemotherapy, GBM has a dismal prognosis and rapid relapsing potential. Hence, search for novel therapeutic agents still continues. Neoantigens are the tumor-specific antigens which arise due to somatic mutations in the tumor genome. In recent years, personalized vaccine approach targeting neoantigens has been explored widely in cancer immunotherapy and several efforts have also been made to revolutionize the immunotherapy of cold tumors such as GBM using neoantigen targeted vaccines.

AREAS COVERED

In this review, we discuss the clinical application of personalized neoantigen targeted vaccine strategy in GBM immunotherapy. While discussing this strategy, we brief about the current challenges faced in GBM treatment by the novel immunotherapeutics.

EXPERT OPINION

To date, very few vaccines developed for GBM have reached till phase III clinical development. Early-phase clinical trials of GBM neoantigen vaccines have shown promising clinical outcomes and therefore, its rapid clinical development is warranted. Advent of newer and faster techniques such as next-generation sequencing will drive the faster clinical development of multiplex neoantigen vaccines and hence, increase in the clinical trials is expected.

Ionizable Lipid Nanoparticle-Mediated mRNA Delivery for Human CAR T Cell Engineering

Chimeric antigen receptor (CAR) T cell therapy relies on the ex vivo manipulation of patient T cells to create potent, cancer-targeting therapies, shown to be capable of inducing remission in patients with acute lymphoblastic leukemia and large B cell lymphoma. However, current CAR T cell engineering methods use viral delivery vectors, which induce permanent CAR expression and could lead to severe adverse effects. Messenger RNA (mRNA) has been explored as a promising strategy for inducing transient CAR expression in T cells to mitigate the adverse effects associated with viral vectors, but it most commonly requires electroporation for T cell mRNA delivery, which can be cytotoxic. Here, ionizable lipid nanoparticles (LNPs) were designed for ex vivo mRNA delivery to human T cells. A library of 24 ionizable lipids was synthesized, formulated into LNPs, and screened for luciferase mRNA delivery to Jurkat cells, revealing seven formulations capable of enhanced mRNA delivery over lipofectamine. The top-performing LNP formulation, C14-4, was selected for CAR mRNA delivery to primary human T cells. This platform induced CAR expression at levels equivalent to electroporation, with substantially reduced cytotoxicity. CAR T cells engineered via C14-4 LNP treatment were then compared to electroporated CAR T cells in a coculture assay with Nalm-6 acute lymphoblastic leukemia cells, and both CAR T cell engineering methods elicited potent cancer-killing activity. These results demonstrate the ability of LNPs to deliver mRNA to primary human T cells to induce functional protein expression, and indicate the potential of LNPs to enhance mRNA-based CAR T cell engineering methods.

Ionizable lipid nanoparticles encapsulating barcoded mRNA for accelerated in vivo delivery screening

Messenger RNA (mRNA) has recently emerged as a promising class of nucleic acid therapy, with the potential to induce protein production to treat and prevent a range of diseases. However, the widespread use of mRNA as a therapeutic requires safe and effective in vivo delivery technologies. Libraries of ionizable lipid nanoparticles (LNPs) have been designed to encapsulate mRNA, prevent its degradation, and mediate intracellular delivery. However, these LNPs are typically characterized and screened in an in vitro setting, which may not fully replicate the biological barriers that they encounter in vivo. Here, we designed and evaluated a library of engineered LNPs containing barcoded mRNA (b-mRNA) to accelerate the screening of mRNA delivery platforms in vivo. These b-mRNA are similar in structure and function to regular mRNA, and contain barcodes that enable their delivery to be quantified via deep sequencing. Using a mini-library of b-mRNA LNPs formulated via microfluidic mixing, we show that these different formulations can be pooled together, administered intravenously into mice as a single pool, and their delivery to multiple organs (liver, spleen, brain, lung, heart, kidney, pancreas, and muscle) can be quantified simultaneously using deep sequencing. In the context of liver and spleen delivery, LNPs that exhibited high b-mRNA delivery also yielded high luciferase expression, indicating that this platform can identify lead LNP candidates as well as optimal formulation parameters for in vivo mRNA delivery. Interestingly, LNPs with identical formulation parameters that encapsulated different types of nucleic acid barcodes (b-mRNA versus a DNA barcode) altered in vivo delivery, suggesting that the structure of the barcoded nucleic acid affects LNP in vivo delivery. This platform, which enables direct barcoding and subsequent quantification of a functional mRNA, can accelerate the in vivo screening and design of LNPs for mRNA therapeutic applications such as CRISPR-Cas9 gene editing, mRNA vaccination, and other mRNA-based regenerative medicine and protein replacement therapies.

Antigen-Inorganic Hybrid Flowers-Based Vaccines with Enhanced Room Temperature Stability and Effective Anticancer Immunity

Particle-based antigen carriers as adjuvants play an important role in vaccine development. Herein, an antigen-inorganic hybrid flower-like particle is developed as a novel vaccine carrier. Model antigen ovalbumin (OVA)-copper (II) sulfate hybrid vaccines (OVA-Cu-HVs) are mildly and facilely constructed through a biomimetic mineralization process. OVA-Cu-HVs facilitate cellular uptake in antigen-presenting cells and the internalization of OVA-Cu-HVs involves macropinocytosis-mediated endocytosis. OVA-Cu-HVs can release OVA in a pH-responsive behavior and promote cytosolic release of antigen to enhance antigen cross-presentation. Immunization with OVA-Cu-HVs promotes the maturation of dendritic cells in draining lymph nodes, induces robust antigen-specific T lymphocyte response, and inhibits tumor growth in vivo. In addition, OVA-Cu-HVs are efficacious after being stored for 4 weeks at room temperature and are expected to simplify vaccine storage and lower the cost of cold storage for transportation. Looking forward, OVA-Cu-HVs may hold strong potential to be as an effective vaccine delivery platform, which will facilitate the application of organic-inorganic hybrid flowers in biomedical areas.

Efficient electroporation of neuronal cells using synthetic oligonucleotides: identifying duplex RNA and antisense oligonucleotide activators of human frataxin expression

Oligonucleotide drugs are experiencing greater success in the clinic, encouraging the initiation of new projects. Resources are insufficient to develop every potentially important project, and persuasive experimental data using cell lines close to disease target tissue is needed to prioritize candidates. Friedreich's ataxia (FRDA) is a devastating and currently incurable disease caused by insufficient expression of the enzyme frataxin (FXN). We have previously shown that synthetic nucleic acids can activate FXN expression in human patient-derived fibroblast cells. We chose to further test these compounds in induced pluripotent stem cell-derived neuronal progenitor cells (iPSC-NPCs). Here we describe methods to deliver oligonucleotides and duplex RNAs into iPSC-NPCs using electroporation. Activation of FXN expression is potent, easily reproducible, and potencies parallel those determined using patient-derived fibroblast cells. A duplex RNA and several antisense oligonucleotides (ASOs) with different combinations of 2'-methoxyethyl (2'-MOE), 2'-fluoro (2'-F), and constrained ethyl (cEt) were active, providing multiple starting points for further development and highlighting improved potency as an important goal for preclinical development. Our data support the conclusion that ASO-mediated activation of FXN is a feasible approach for treating FRDA and that electroporation is a robust method for introducing ASOs to modulate gene expressions in neuronal cells.

Co-delivery of immunomodulators in biodegradable nanoparticles improves therapeutic efficacy of cancer vaccines

To improve the efficacy of cancer vaccines we aimed to modulate the suppressive tumor microenvironment. In this study, the potential of intratumoral immune modulation with poly (I:C), Resiquimod (R848) and CCL20 (MIP3α) was explored. Biodegradable polymeric nanoparticles were used as delivery vehicles for slow and sustained release of these drugs in the tumor area and were combined with specific immunotherapy based on therapeutic peptide vaccination in two aggressive murine carcinoma and lymphoma tumor models. Whereas nanoparticle delivery of poly (I:C) or R848 improved therapeutic efficacy, the combination with MIP3α remarkably potentiated the cancer vaccine antitumor effects. The long-term survival increased to 75-100% and the progression free survival nearly doubled on mice with established large carcinoma tumors. The potent adjuvant effects were associated with lymphoid and myeloid population alterations in the tumor and tumor-draining lymph node. In addition to a significant influx of macrophages into the tumor, the phenotype of the suppressor tumor-associated macrophages shifted towards an acute inflammatory phenotype in the tumor-draining lymph node. Overall, these data show that therapeutic cancer vaccines can be potentiated by the combined nanoparticle mediated co-delivery of poly (I:C), R848 and MIP3α, which indicates that a more favorable milieu for cancer fighting immune cells is created for T cells induced by therapeutic cancer vaccines.

At the Intersection of Biomaterials and Gene Therapy: Progress in Non-viral Delivery of Nucleic Acids

Biomaterials play a critical role in technologies intended to deliver therapeutic agents in clinical settings. Recent explosion of our understanding of how cells utilize nucleic acids has garnered excitement to develop a range of older (e.g., antisense oligonucleotides, plasmid DNA and transposons) and emerging (e.g., short interfering RNA, messenger RNA and non-coding RNAs) nucleic acid agents for therapy of a wide range of diseases. This review will summarize biomaterials-centered advances to undertake effective utilization of nucleic acids for therapeutic purposes. We first review various types of nucleic acids and their unique abilities to deliver a range of clinical outcomes. Using recent advances in T-cell based therapy as a case in point, we summarize various possibilities for utilizing biomaterials to make an impact in this exciting therapeutic intervention technology, with the belief that this modality will serve as a therapeutic paradigm for other types of cellular therapies in the near future. We subsequently focus on contributions of biomaterials in emerging nucleic acid technologies, specifically focusing on the design of intelligent nanoparticles, deployment of mRNA as an alternative to plasmid DNA, long-acting (integrating) expression systems, and in vitro/in vivo expansion of engineered T-cells. We articulate the role of biomaterials in these emerging nucleic acid technologies in order to enhance the clinical impact of nucleic acids in the near future.

Liposomal Antitumor Vaccines Targeting Mucin 1 Elicit a Lipid-Dependent Immunodominant Response

The tumor-associated antigen mucin 1 (MUC1) has been pursued as an attractive target for cancer immunotherapy, but the poor immunogenicity of the endogenous antigen hinders the development of vaccines capable of inducing effective anti-MUC1 immunodominant responses. Herein, we prepared synthetic anti-MUC1 vaccines in which the hydrophilic MUC1 antigen was N-terminally conjugated to one or two palmitoyl lipid chains (to form amphiphilic Pam-MUC1 or Pam₂ -MUC1). These amphiphilic lipid-tailed MUC1 antigens were self-assembled into liposomes containing the NKT cell agonist αGalCer as an adjuvant. The lipid-conjugated antigens reshaped the physical and morphological properties of liposomal vaccines. Promising results showed that the anti-MUC1 IgG antibody titers induced by the Pam₂ -MUC1 vaccine were more than 30- and 190-fold higher than those induced by the Pam-MUC1 vaccine and the MUC1 vaccine without lipid tails, respectively. Similarly, vaccines with the TLR1/2 agonist Pam₃ CSK₄ as an adjuvant also induced conjugated lipid-dependent immunological responses. Moreover, vaccines with the αGalCer adjuvant induced significantly higher titers of IgG antibodies than vaccines with the Pam₃ CSK₄ adjuvant. Therefore, the non-covalent assembly of the amphiphilic lipo-MUC1 antigen and the NKT cell agonist αGalCer as a glycolipid adjuvant represent a synthetically simple but immunologically effective approach for the development of anti-MUC1 cancer vaccines.

Nanoparticles for nucleic acid delivery: Applications in cancer immunotherapy

Immunotherapy has recently emerged as a powerful tool for cancer treatment. Early clinical successes from cancer immunotherapy have led to a growing list of FDA approvals, and many new therapies are in clinical and preclinical development. Nucleic acid therapeutics, including DNA, mRNA, and genome editing systems, hold significant potential as a form of immunotherapy due to its robust use in cancer vaccination, adoptive T-cell therapy, and gene regulation. However, these therapeutics must overcome numerous delivery obstacles to be successful, including rapid in vivo degradation, poor uptake into target cells, required nuclear entry, and potential in vivo toxicity in healthy cells and tissues. Nanoparticle delivery systems have been engineered to overcome several of these barriers as a means to safely and effectively deliver nucleic acid therapeutics to immune cells. In this Review, we discuss the applications of nucleic acid therapeutics in cancer immunotherapy, and we detail how nanoparticle platforms have been designed to deliver mRNA, DNA, and genome editing systems to enhance the potency and safety of these therapeutics.

Advances in mRNA Vaccines for Infectious Diseases

During the last two decades, there has been broad interest in RNA-based technologies for the development of prophylactic and therapeutic vaccines. Preclinical and clinical trials have shown that mRNA vaccines provide a safe and long-lasting immune response in animal models and humans. In this review, we summarize current research progress on mRNA vaccines, which have the potential to be quick-manufactured and to become powerful tools against infectious disease and we highlight the bright future of their design and applications.

Concepts of nanoparticle cellular uptake, intracellular trafficking, and kinetics in nanomedicine

Nanoparticle-based therapeutics and diagnostics are commonly referred to as nanomedicine and may significantly impact the future of healthcare. However, the clinical translation of these technologies is challenging. One of these challenges is the efficient delivery of nanoparticles to specific cell populations and subcellular targets in the body to elicit desired biological and therapeutic responses. It is critical for researchers to understand the fundamental concepts of how nanoparticles interact with biological systems to predict and control in vivo nanoparticle transport for improved clinical benefit. In this overview article, we review and discuss cellular internalization pathways, summarize the field`s understanding of how nanoparticle physicochemical properties affect cellular interactions, and explore and discuss intracellular nanoparticle trafficking and kinetics. Our overview may provide a valuable resource for researchers and may inspire new studies to expand our current understanding of nanotechnology-biology interactions at cellular and subcellular levels with the goal to improve clinical translation of nanomedicines.