mRNA-based dendritic cell vaccines

Clinical and immunological effects of mRNA vaccines in malignant diseases

In vitro-transcribed messenger RNA-based therapeutics represent a relatively novel and highly efficient class of drugs. Several recently published studies emphasize the potential efficacy of mRNA vaccines in treating different types of malignant and infectious diseases where conventional vaccine strategies and platforms fail to elicit protective immune responses. mRNA vaccines have lately raised high interest as potent vaccines against SARS-CoV2. Direct application of mRNA or its electroporation into dendritic cells was shown to induce polyclonal CD4+ and CD8+ mediated antigen-specific T cell responses as well as the production of protective antibodies with the ability to eliminate transformed or infected cells. More importantly, the vaccine composition may include two or more mRNAs coding for different proteins or long peptides. This enables the induction of polyclonal immune responses against a broad variety of epitopes within the encoded antigens that are presented on various MHC complexes, thus avoiding the restriction to a certain HLA molecule or possible immune escape due to antigen-loss. The development and design of mRNA therapies was recently boosted by several critical innovations including the development of technologies for the production and delivery of high quality and stable mRNA. Several technical obstacles such as stability, delivery and immunogenicity were addressed in the past and gradually solved in the recent years.This review will summarize the most recent technological developments and application of mRNA vaccines in clinical trials and discusses the results, challenges and future directions with a special focus on the induced innate and adaptive immune responses.

Enhanced anti-inflammatory effects of mesenchymal stromal cells mediated by the transient ectopic expression of CXCR4 and IL10

Background

Mesenchymal stromal cells (MSCs) constitute one of the cell types most frequently used in cell therapy. Although several studies have shown the efficacy of these cells to modulate inflammation in different animal models, the results obtained in human clinical trials have been more modest. Here, we aimed at improving the therapeutic properties of MSCs by inducing a transient expression of two molecules that could enhance two different properties of these cells. With the purpose of improving MSC migration towards inflamed sites, we induced a transient expression of the C-X-C chemokine receptor type 4 (CXCR4). Additionally, to augment the anti-inflammatory properties of MSCs, a transient expression of the anti-inflammatory cytokine, interleukin 10 (IL10), was also induced.

Methods

Human adipose tissue-derived MSCs were transfected with messenger RNAs carrying the codon-optimized versions of CXCR4 and/or IL10. mRNA-transfected MSCs were then studied, first to evaluate whether the characteristic phenotype of MSCs was modified. Additionally, in vitro and also in vivo studies in an LPS-induced inflamed pad model were conducted to evaluate the impact associated to the transient expression of CXCR4 and/or IL10 in MSCs.

Results

Transfection of MSCs with CXCR4 and/or IL10 mRNAs induced a transient expression of these molecules without modifying the characteristic phenotype of MSCs. In vitro studies then revealed that the ectopic expression of CXCR4 significantly enhanced the migration of MSCs towards SDF-1, while an increased immunosuppression was associated with the ectopic expression of IL10. Finally, in vivo experiments showed that the co-expression of CXCR4 and IL10 increased the homing of MSCs into inflamed pads and induced an enhanced anti-inflammatory effect, compared to wild-type MSCs.

Conclusions

Our results demonstrate that the transient co-expression of CXCR4 and IL10 enhances the therapeutic potential of MSCs in a local inflammation mouse model, suggesting that these mRNA-modified cells may constitute a new step in the development of more efficient cell therapies for the treatment of inflammatory diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02193-0.

Coding potential of circRNAs: new discoveries and challenges

The circular (circ)RNAs are a newly recognized group of noncoding (nc)RNAs. Research to characterize the functional features of circRNAs has uncovered distinctive profiles of conservation, stability, specificity and complexity. However, a new line of evidence has indicated that although circRNAs can function as ncRNAs, such as in the role of miRNA sponges, they are also capable of coding proteins. This discovery is no accident. In the last century, scientist detected the ability of translate in some virus and artificial circRNAs. Artificial circRNA translation products are usually nonfunctional, whereas natural circRNA translation products are completely different. Those new proteins have various functions, which greatly broadens the new ideas and research direction for our research. These series findings also raise questions about whether circRNA is still classified as non-coding RNA. Here, we summarize the evidence concerning translation potential of circRNAs, including synthetic and endogenous circRNA translation ability, and discuss the mechanisms of circRNA translation.

Vaccination with Messenger RNA: A Promising Alternative to DNA Vaccination

The first proof-of-concept studies about the feasibility of genetic vaccines were published over three decades ago, opening the way for future development. The idea of nonviral antigen delivery had multiple advantages over the traditional live or inactivated pathogen-based vaccines, but a great deal of effort had to be invested to turn the idea of genetic vaccination into reality. Although early proof-of-concept studies were groundbreaking, they also showed that numerous aspects of genetic vaccines needed to be improved. Until the early 2000s, the vast majority of effort was invested into the development of DNA vaccines due to the potential issues of instability and low in vivo translatability of messenger RNA (mRNA). In recent years, numerous studies have demonstrated the outstanding abilities of mRNA to elicit potent immune responses against infectious pathogens and different types of cancer, making it a viable platform for vaccine development. Multiple mRNA vaccine platforms have been developed and evaluated in small and large animals and humans and the results seem to be promising. RNA-based vaccines have important advantages over other vaccine approaches including outstanding efficacy, safety, and the potential for rapid, inexpensive, and scalable production. There is a substantial investment by new mRNA companies into the development of mRNA therapeutics, particularly vaccines, increasing the number of basic and translational research publications and human clinical trials underway. This review gives a broad overview about genetic vaccines and mainly focuses on the past and present of mRNA vaccines along with the future directions to bring this potent vaccine platform closer to therapeutic use.

Adjuvant-pulsed mRNA vaccine nanoparticle for immunoprophylactic and therapeutic tumor suppression in mice

Synthetic mRNA represents an exciting cancer vaccine technology for the implementation of effective cancer immunotherapy. However, inefficient in vivo mRNA delivery along with a requirement for immune co-stimulation present major hurdles to achieving anti-tumor therapeutic efficacy. Here, we demonstrate a proof-of-concept adjuvant-pulsed mRNA vaccine nanoparticle (NP) that is composed of an ovalbumin-coded mRNA and a palmitic acid-modified TLR7/8 agonist R848 (C16-R848), coated with a lipid-polyethylene glycol (lipid-PEG) shell. This mRNA vaccine NP formulation retained the adjuvant activity of encapsulated C16-R848 and markedly improved the transfection efficacy of the mRNA (>95%) and subsequent MHC class I presentation of OVA mRNA derived antigen in antigen-presenting cells. The C16-R848 adjuvant-pulsed mRNA vaccine NP approach induced an effective adaptive immune response by significantly improving the expansion of OVA-specific CD8+ T cells and infiltration of these cells into the tumor bed in vivo, relative to the mRNA vaccine NP without adjuvant. The approach led to an effective anti-tumor immunity against OVA expressing syngeneic allograft mouse models of lymphoma and prostate cancer, resulting in a significant prevention of tumor growth when the vaccine was given before tumor engraftment (84% reduction vs. control) and suppression of tumor growth when given post engraftment (60% reduction vs. control). Our findings indicate that C16-R848 adjuvant pulsation to mRNA vaccine NP is a rational design strategy to increase the effectiveness of synthetic mRNA vaccines for cancer immunotherapy.

Neo-Antigen mRNA Vaccines

The interest in therapeutic cancer vaccines has caught enormous attention in recent years due to several breakthroughs in cancer research, among which the finding that successful checkpoint blockade treatments reinvigorate neo-antigen-specific T cells and that successful adoptive cell therapies are directed towards neo-antigens. Neo-antigens are cancer-specific antigens, which develop from somatic mutations in the cancer cell genome that can be highly immunogenic and are not subjected to central tolerance. As the majority of neo-antigens are unique to each patient's cancer, a vaccine technology that is flexible and potent is required to develop personalized neo-antigen vaccines. In vitro transcribed mRNA is such a technology platform and has been evaluated for delivery of neo-antigens to professional antigen-presenting cells both ex vivo and in vivo. In addition, strategies that support the activity of T cells in the tumor microenvironment have been developed. These represent a unique opportunity to ensure durable T cell activity upon vaccination. Here, we comprehensively review recent progress in mRNA-based neo-antigen vaccines, summarizing critical milestones that made it possible to bring the promise of therapeutic cancer vaccines within reach.

Maturation of Monocyte-Derived DCs Leads to Increased Cellular Stiffness, Higher Membrane Fluidity, and Changed Lipid Composition

Dendritic cells (DCs) are professional antigen-presenting cells of the immune system. Upon sensing pathogenic material in their environment, DCs start to mature, which includes cellular processes, such as antigen uptake, processing and presentation, as well as upregulation of costimulatory molecules and cytokine secretion. During maturation, DCs detach from peripheral tissues, migrate to the nearest lymph node, and find their way into the correct position in the net of the lymph node microenvironment to meet and interact with the respective T cells. We hypothesize that the maturation of DCs is well prepared and optimized leading to processes that alter various cellular characteristics from mechanics and metabolism to membrane properties. Here, we investigated the mechanical properties of monocyte-derived dendritic cells (moDCs) using real-time deformability cytometry to measure cytoskeletal changes and found that mature moDCs were stiffer compared to immature moDCs. These cellular changes likely play an important role in the processes of cell migration and T cell activation. As lipids constitute the building blocks of the plasma membrane, which, during maturation, need to adapt to the environment for migration and DC-T cell interaction, we performed an unbiased high-throughput lipidomics screening to identify the lipidome of moDCs. These analyses revealed that the overall lipid composition was significantly changed during moDC maturation, even implying an increase of storage lipids and differences of the relative abundance of membrane lipids upon maturation. Further, metadata analyses demonstrated that lipid changes were associated with the serum low-density lipoprotein (LDL) and cholesterol levels in the blood of the donors. Finally, using lipid packing imaging we found that the membrane of mature moDCs revealed a higher fluidity compared to immature moDCs. This comprehensive and quantitative characterization of maturation associated changes in moDCs sets the stage for improving their use in clinical application.

Single-cell transfection technologies for cell therapies and gene editing

Advances in gene editing and cell therapies have recently led to outstanding clinical successes. However, the lack of a cost-effective manufacturing process prevents the democratization of these innovative medical tools. Due to the common use of viral vectors, the step of transfection in which cells are engineered to gain new functions, is a major bottleneck in making safe and affordable cell products. A promising opportunity lies in Single-Cell Transfection Technologies (SCTTs). SCTTs have demonstrated higher efficiency, safety and scalability than conventional transfection methods. They can also feature unique abilities such as substantial dosage control over the cargo delivery, single-cell addressability and integration in microdevices comprising multiple monitoring modalities. Unfortunately, the potential of SCTTs is not fully appreciated: they are most often restricted to research settings with little adoption in clinical settings. To encourage their adoption, we review and compare recent developments in SCTTs, and how they can enable selected clinical applications. To help bridge the gap between fundamental research and its translation to the clinic, we also describe how Good Manufacturing Practices (GMP) can be integrated in the design of SCTTs.

Promoting the activation of T cells with glycopolymer-modified dendritic cells by enhancing cell interactions

Dendritic cell (DC) modification to enhance antigen presentation is a valuable strategy in cancer immune therapy. Other than focusing on regulating interactions between DC and antigens, we intend to promote cell interactions between DC and T cell by cell surface engineering. T cell activation is greatly improved and generates higher tumor toxicity with the aid of the synthetic glycopolymer modified on the DC surface, although the glycopolymer alone shows no effect. The great promotion of DC-T cell attraction is revealed by cell image tracking in terms of both frequency and duration of contacts. Our findings provide a new method of T cell activation by these engineered "sweet DCs." This strategy is beneficial for developing more efficient DC-based vaccines.

Engineering Antiviral Vaccines

Despite the vital role of vaccines in fighting viral pathogens, effective vaccines are still unavailable for many infectious diseases. The importance of vaccines cannot be overstated during the outbreak of a pandemic, such as the coronavirus disease 2019 (COVID-19) pandemic. The understanding of genomics, structural biology, and innate/adaptive immunity have expanded the toolkits available for current vaccine development. However, sudden outbreaks and the requirement of population-level immunization still pose great challenges in today's vaccine designs. Well-established vaccine development protocols from previous experiences are in place to guide the pipelines of vaccine development for emerging viral diseases. Nevertheless, vaccine development may follow different paradigms during a pandemic. For example, multiple vaccine candidates must be pushed into clinical trials simultaneously, and manufacturing capability must be scaled up in early stages. Factors from essential features of safety, efficacy, manufacturing, and distributions to administration approaches are taken into consideration based on advances in materials science and engineering technologies. In this review, we present recent advances in vaccine development by focusing on vaccine discovery, formulation, and delivery devices enabled by alternative administration approaches. We hope to shed light on developing better solutions for faster and better vaccine development strategies through the use of biomaterials, biomolecular engineering, nanotechnology, and microfabrication techniques.

Physical transfection technologies for macrophages and dendritic cells in immunotherapy

INTRODUCTION

Dendritic cells (DCs) and macrophages, two important antigen presenting cells (APCs) of the innate immune system, are being explored for the use in cell-based cancer immunotherapy. For this application, the therapeutic potential of patient-derived APCs is increased by delivering different types of functional macromolecules, such as mRNA and pDNA, into their cytosol. Compared to the use of viral and non-viral delivery vectors, physical intracellular delivery techniques are known to be more straightforward, more controllable, faster and generate high delivery efficiencies.

AREAS COVERED

This review starts with electroporation as the most traditional physical transfection method, before continuing with the more recent technologies such as sonoporation, nanowires and microfluidic cell squeezing. A description is provided of each of those intracellular delivery technologies with their strengths and weaknesses, especially paying attention to delivery efficiency and safety profile.

EXPERT OPINION

Given the common use of electroporation for the production of therapeutic APCs, it is recommended that more detailed studies are performed on the effect of electroporation on APC fitness, even down to the genetic level. Newer intracellular delivery technologies seem to have less impact on APC functionality but further work is needed to fully uncover their suitability to transfect APCs with different types of macromolecules.

Emerging Concepts and Technologies in Vaccine Development

Despite the success of vaccination to greatly mitigate or eliminate threat of diseases caused by pathogens, there are still known diseases and emerging pathogens for which the development of successful vaccines against them is inherently difficult. In addition, vaccine development for people with compromised immunity and other pre-existing medical conditions has remained a major challenge. Besides the traditional inactivated or live attenuated, virus-vectored and subunit vaccines, emerging non-viral vaccine technologies, such as viral-like particle and nanoparticle vaccines, DNA/RNA vaccines, and rational vaccine design, offer innovative approaches to address existing challenges of vaccine development. They have also significantly advanced our understanding of vaccine immunology and can guide future vaccine development for many diseases, including rapidly emerging infectious diseases, such as COVID-19, and diseases that have not traditionally been addressed by vaccination, such as cancers and substance abuse. This review provides an integrative discussion of new non-viral vaccine development technologies and their use to address the most fundamental and ongoing challenges of vaccine development.

mRNA Vaccine Era-Mechanisms, Drug Platform and Clinical Prospection

Messenger ribonucleic acid (mRNA)-based drugs, notably mRNA vaccines, have been widely proven as a promising treatment strategy in immune therapeutics. The extraordinary advantages associated with mRNA vaccines, including their high efficacy, a relatively low severity of side effects, and low attainment costs, have enabled them to become prevalent in pre-clinical and clinical trials against various infectious diseases and cancers. Recent technological advancements have alleviated some issues that hinder mRNA vaccine development, such as low efficiency that exist in both gene translation and in vivo deliveries. mRNA immunogenicity can also be greatly adjusted as a result of upgraded technologies. In this review, we have summarized details regarding the optimization of mRNA vaccines, and the underlying biological mechanisms of this form of vaccines. Applications of mRNA vaccines in some infectious diseases and cancers are introduced. It also includes our prospections for mRNA vaccine applications in diseases caused by bacterial pathogens, such as tuberculosis. At the same time, some suggestions for future mRNA vaccine development about storage methods, safety concerns, and personalized vaccine synthesis can be found in the context.

Recent developments of RNA-based vaccines in cancer immunotherapy

INTRODUCTION

Cancer immunotherapy is more dependent on monoclonal antibodies, proteins, and cells, as therapeutic agents, to attain prominent outcomes. However, cancer immunotherapy's clinical benefits need to be enhanced, as many patients still do not respond well to existing treatments, or their diseases may relapse after temporary control. RNA-based approaches have provided new options for advancing cancer immunotherapy. Moreover, considerable efforts have been made to utilize RNA for vaccine production. RNA vaccines, which encode tumor-associated or specific epitopes, stimulate adaptive immunity. This adaptive immune response is capable of elimination or reduction of tumor burden. It is crucial to develop effective RNA transfer technologies that penetrate the lipid bilayer to reach the cytoplasm for translation into functional proteins. Two important delivery methods include the loading of mRNA into dendritic cells ex vivo; and direct injection of naked RNA with or without a carrier.

AREAS COVERED

The latest results of pre-clinical and clinical studies with RNA vaccines in cancer immunotherapy are summarized in this review.

EXPERT OPINION

RNA vaccines are now in early clinical development with promising safety and efficacy outcomes. Also, the translation capacity and durability of these vaccines can be increased with chemical modifications and sequence engineering.

Dendritic cell biology and its role in tumor immunotherapy

As crucial antigen presenting cells, dendritic cells (DCs) play a vital role in tumor immunotherapy. Taking into account the many recent advances in DC biology, we discuss how DCs (1) recognize pathogenic antigens with pattern recognition receptors through specific phagocytosis and through non-specific micropinocytosis, (2) process antigens into small peptides with proper sizes and sequences, and (3) present MHC-peptides to CD4⁺ and CD8⁺ T cells to initiate immune responses against invading microbes and aberrant host cells. During anti-tumor immune responses, DC-derived exosomes were discovered to participate in antigen presentation. T cell microvillar dynamics and TCR conformational changes were demonstrated upon DC antigen presentation. Caspase-11-driven hyperactive DCs were recently reported to convert effectors into memory T cells. DCs were also reported to crosstalk with NK cells. Additionally, DCs are the most important sentinel cells for immune surveillance in the tumor microenvironment. Alongside DC biology, we review the latest developments for DC-based tumor immunotherapy in preclinical studies and clinical trials. Personalized DC vaccine-induced T cell immunity, which targets tumor-specific antigens, has been demonstrated to be a promising form of tumor immunotherapy in patients with melanoma. Importantly, allogeneic-IgG-loaded and HLA-restricted neoantigen DC vaccines were discovered to have robust anti-tumor effects in mice. Our comprehensive review of DC biology and its role in tumor immunotherapy aids in the understanding of DCs as the mentors of T cells and as novel tumor immunotherapy cells with immense potential.

Current RNA-based Therapeutics in Clinical Trials

Long-term research on various types of RNAs has led to further understanding of diverse mechanisms, which eventually resulted in the rapid development of RNA-based therapeutics as powerful tools in clinical disease treatment. Some of the developing RNA drugs obey the antisense mechanisms including antisense oligonucleotides, small interfering RNAs, microRNAs, small activating RNAs, and ribozymes. These types of RNAs could be utilized to inhibit/activate gene expression or change splicing to provide functional proteins. In the meantime, some others based on different mechanisms like modified messenger RNAs could replace the dysfunctional endogenous genes to manage some genetic diseases, and aptamers with special three-dimensional structures could bind to specific targets in a high-affinity manner. In addition, the recent most popular CRISPR-Cas technology, consisting of a crucial single guide RNA, could edit DNA directly to generate therapeutic effects. The desired results from recent clinical trials indicated the great potential of RNA-based drugs in the treatment of various diseases, but further studies on improving delivery materials and RNA modifications are required for the novel RNA-based drugs to translate to the clinic. This review focused on the advances and clinical studies of current RNA-based therapeutics, analyzed their challenges and prospects.

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.

Clinical applications of extracellular vesicle long RNAs

Extracellular vesicles (EVs), primarily exosomes and microvesicles, are critical intercellular mediators of communication. Over the past decade, improved knowledge and methodologies have enabled the detection and quantification of RNA species in EVs, despite their extremely low levels. Recently, EV-associated long RNAs (exLRs) have been drawing much attention. Delivered by EVs, they have higher stability, greater difference in temporal and spatial expression, and the capacity to remodel both proximal and distal recipient cells. These properties guarantee their roles as biomarkers, therapeutic targets, vaccines, and gene therapy agents in a wide range of human diseases. Despite the progress in this area of research, limitations in both knowledge and methodologies have hindered its further development. Herein, we comprehensively reviewed studies related to exLRs, including protein-coding messenger RNAs (mRNAs) and noncoding RNAs (long noncoding RNAs and circular RNAs) in EVs to indicate their value in the diagnosis and treatment of human diseases; we also present a series of yet unsettled issues in this novel area, hence providing insights for future studies.

The challenge and prospect of mRNA therapeutics landscape

Messenger RNA (mRNA)-based therapeutics hold the potential to cause a major revolution in the pharmaceutical industry because they can be used for precise and individualized therapy, and enable patients to produce therapeutic proteins in their own bodies without struggling with the comprehensive manufacturing issues associated with recombinant proteins. Compared with the current therapeutics, the production of mRNA is much cost-effective, faster and more flexible because it can be easily produced by in vitro transcription, and the process is independent of mRNA sequence. Moreover, mRNA vaccines allow people to develop personalized medications based on sequencing results and/or personalized conditions rapidly. Along with the great potential from bench to bedside, technical obstacles facing mRNA pharmaceuticals are also obvious. The stability, immunogenicity, translation efficiency, and delivery are all pivotal issues need to be addressed. In the recently published research results, these issues are gradually being overcome by state-of-the-art development technologies. In this review, we describe the structural properties and modification technologies of mRNA, summarize the latest advances in developing mRNA delivery systems, review the preclinical and clinical applications, and put forward our views on the prospect and challenges of developing mRNA into a new class of drug.

Nanoparticles versus Dendritic Cells as Vehicles to Deliver mRNA Encoding Multiple Epitopes for Immunotherapy

The efficacy of antigen-specific immunotherapy relies heavily on efficient antigen delivery to antigen-presenting cells and engagement of as many disease-relevant T cells as possible in various lymphoid tissues, which are challenging to achieve. Here, we compared two approaches to deliver mRNA encoding multiple epitopes targeting both CD4⁺ and CD8⁺ T cells: a lipid-based nanoparticle platform to target endogenous antigen-presenting cells in vivo versus ex vivo mRNA-electroporated dendritic cells. After intraperitoneal injection, the nanoparticle platform facilitated efficient entry of mRNA into various endogenous antigen-presenting cells, including lymph node stromal cells, and elicited robust T cell responses within a wider network of lymphoid tissues compared with dendritic cells. Following intravenous injection, mRNA-electroporated dendritic cells and the nanoparticle platform localized primarily in lung and spleen, respectively. When administered locally via an intradermal route, both platforms resulted in mRNA expression at the injection site and in robust T cell responses in draining lymph nodes. This study indicates that multiple epitopes, customizable for specific patient populations and encoded by mRNA, can be targeted to different lymphoid tissues based on delivery vehicle and route, and constitute the groundwork for future studies using mRNA to reprogram exogenous or endogenous APCs for immunotherapy.

Single Domain Antibody-Mediated Blockade of Programmed Death-Ligand 1 on Dendritic Cells Enhances CD8 T-cell Activation and Cytokine Production

Dendritic cell [DC] vaccines can induce durable clinical responses, at least in a fraction of previously treated, late stage cancer patients. Several preclinical studies suggest that shielding programmed death-ligand 1 [PD-L1] on the DC surface may be an attractive strategy to extend such clinical benefits to a larger patient population. In this study, we evaluated the use of single domain antibody [sdAb] K2, a high affinity, antagonistic, PD-L1 specific sdAb, for its ability to enhance DC mediated T-cell activation and benchmarked it against the use of the monoclonal antibodies [mAbs], MIH1, 29E.2A3 and avelumab. Similar to mAbs, sdAb K2 enhanced antigen-specific T-cell receptor signaling in PD-1 positive (PD-1^pos) reporter cells activated by DCs. We further showed that the activation and function of antigen-specific CD8 positive (CD8^pos) T cells, activated by DCs, was enhanced by inclusion of sdAb K2, but not mAbs. The failure of mAbs to enhance T-cell activation might be explained by their low efficacy to bind PD-L1 on DCs when compared to binding of PD-L1 on non-immune cells, whereas sdAb K2 shows high binding to PD-L1 on immune as well as non-immune cells. These data provide a rationale for the inclusion of sdAb K2 in DC-based immunotherapy strategies.

Immunotherapy a New Hope for Cancer Treatment: A Review

Cancer is a major burden of disease worldwide with considerable impact on society. The tide of immunotherapy has finally changed after decades of disappointing results and has become a clinically validated treatment for many cancers. Immunotherapy takes many forms in cancer treatment, including the adoptive transfer of ex vivo activated T cells, oncolytic viruses, natural killer cells, cancer vaccines and administration of antibodies or recombinant proteins that either costimulate cells or block the so-called immune checkpoint pathways. Recently, cancer immunotherapy has received a high degree of attention, which mainly contains the treatments for programmed death ligand 1 (PD-L1), programmed death 1 (PD-1), chimeric antigen receptors (CARs) and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4). Here, this paper reviewed the current understandings of the main strategies in cancer immunotherapy (adoptive cellular immunotherapy, immune checkpoint blockade, oncolytic viruses and cancer vaccines) and discuss the progress in the synergistic design of immune-targeting combination therapies.

mRNA as a Transformative Technology for Vaccine Development to Control Infectious Diseases

In the last two decades, there has been growing interest in mRNA-based technology for the development of prophylactic vaccines against infectious diseases. Technological advancements in RNA biology, chemistry, stability, and delivery systems have accelerated the development of fully synthetic mRNA vaccines. Potent, long-lasting, and safe immune responses observed in animal models, as well as encouraging data from early human clinical trials, make mRNA-based vaccination an attractive alternative to conventional vaccine approaches. Thanks to these data, together with the potential for generic, low-cost manufacturing processes and the completely synthetic nature, the prospects for mRNA vaccines are very promising. In addition, mRNA vaccines have the potential to streamline vaccine discovery and development, and facilitate a rapid response to emerging infectious diseases. In this review, we overview the unique attributes of mRNA vaccine approaches, review the data of mRNA vaccines against infectious diseases, discuss the current challenges, and highlight perspectives about the future of this promising technology.

Injectable Biodegradable Chitosan-Alginate 3D Porous Gel Scaffold for mRNA Vaccine Delivery

mRNA vaccines have proven to be more stable, effective, and specific than protein/peptide-based vaccines in stimulating both humoral and cellular immune response. However, mRNA's fast degradation rate and low-transfection efficiency in vivo impede its potential in vaccination. Recent research in gene delivery has focused on nonviral vaccine carriers and either implantable or injectable delivery systems to improve transgene expression in vivo. Here, an injectable chitosan-alginate gel scaffold for the local delivery of mRNA vaccines is reported. Gel scaffold biodegradation rates and biocompatibility are quantified. Scaffold-mediated mRNA in vivo transgene expression as well as ovalbumin antigen specific cellular and humoral immune responses are evaluated in vivo. Luciferase reporter protein expression resulting from mRNA lipoplex-loaded gel scaffolds is five times higher than systemic injection. Compared to systemic injections of naked mRNA or mRNA:lipoplexes, elevated levels of T cell proliferation and IFN-γ secretion are seen with in vivo scaffold-mediated mRNA lipoplex delivery. Furthermore, a humoral response (ovalbumin antigen specific IgG levels) is observed as early as week 1 for scaffold-mediated mRNA lipoplex delivery, while protein-based immunization did not elicit IgG production until 2 weeks post-injection. Results suggest that injectable scaffold mRNA vaccine delivery maybe a viable alternative to traditional nucleic acid immunization methods.

Poly(lactic acid) nanoparticles and cell-penetrating peptide potentiate mRNA-based vaccine expression in dendritic cells triggering their activation

Messenger RNA-based vaccines have the potential to trigger robust cytotoxic immune responses, which are essential for fighting cancer and infectious diseases like HIV. Dendritic Cells (DCs) are choice targets for mRNA-based vaccine strategies, as they link innate and adaptive immune responses and are major regulators of cytotoxic and humoral adaptive responses. However, efficient delivery of antigen-coding mRNAs into DC cytosol has been highly challenging. In this study, we developed an alternative to lipid-based mRNA delivery systems, using poly(lactic acid) nanoparticles (PLA-NPs) and cationic cell-penetrating peptides as mRNA condensing agent. The formulations are assembled in two steps: (1) formation of a polyplex between mRNAs and amphipathic cationic peptides (RALA, LAH4 or LAH4-L1), and (2) adsorption of polyplexes onto PLA-NPs. LAH4-L1/mRNA polyplexes and PLA-NP/LAH4-L1/mRNA nanocomplexes are taken up by DCs via phagocytosis and clathrin-dependent endocytosis, and induce strong protein expression in DCs in vitro. They modulate DC innate immune response by activating both endosome and cytosolic Pattern Recognition Receptors (PRRs), and induce markers of adaptive responses in primary human DCs in vitro, with prevalent Th1 signature. Thus, LAH4-L1/mRNA and PLA-NP/LAH4-L1/mRNA represent a promising platform for ex vivo treatment and mRNA vaccine development.

A universal anti-cancer vaccine: Chimeric invariant chain potentiates the inhibition of melanoma progression and the improvement of survival

For many years, clinicians and scientists attempt to develop methods to stimulate the immune system to target malignant cells. Recent data suggest that effective cancer vaccination requires combination immunotherapies to overcome tumor immune evasion. Through presentation of both MHC-I and II molecules, DCs-based vaccine platforms are effective in generating detectable CD4 and CD8 T cell responses against tumor-associated antigens. Several platforms include DC transfection with mRNA of the desired tumor antigen. These DCs are then delivered to the host and elicit an immune response against the antigen of interest. We have recently established an mRNA genetic platform which induced specific CD8⁺ cytotoxic T cell response by DC vaccination against melanoma. In our study, an MHC-II mRNA DCs vaccine platform was developed to activate CD4⁺ T cells and to enhance the anti-tumor response. The invariant chain (Ii) was modified and the semi-peptide CLIP was replaced with an MHC-II binding peptide sequences of melanoma antigens. These chimeric MHC-II constructs are presented by DCs and induce proliferation of tumor specific CD4⁺ T cells. When administered in combination with the MHC-I platform into tumor bearing mice, these constructs were able to inhibit tumor growth, and improve mouse survival. Deciphering the immunological mechanism of action, we observed an efficient CTLs killing in addition to higher levels of Th1 and Th2 subsets in the groups immunized with a combination of the MHC-I and MHC-II constructs. These universal constructs can be applied in multiple combinations and offer an attractive opportunity to improve cancer treatment.

An autologous dendritic cell vaccine polarizes a Th-1 response which is tumoricidal to patient-derived breast cancer cells

Breast cancer remains one of the leading causes of cancer-associated death worldwide. Conventional treatment is associated with substantial toxicity and suboptimal efficacy. We, therefore, developed and evaluated the in vitro efficacy of an autologous dendritic cell (DC) vaccine to treat breast cancer. We recruited 12 female patients with stage 1, 2, or 3 breast cancer and matured their DCs with autologous tumour-specific lysate, a toll-like receptor (TLR)-3 and 7/8 agonist, and an interferon-containing cocktail. The efficacy of the vaccine was evaluated by its ability to elicit a cytotoxic T-lymphocyte response to autologous breast cancer cells in vitro. Matured DCs (≥ 60% upregulation of CD80, CD86, CD83, and CCR7) produced high levels of the Th1 effector cytokine, IL12-p70 (1.2 ng/ml; p < 0.0001), compared to DCs pulsed with tumour lysate, or matured with an interferon-containing cocktail alone. We further showed that matured DCs enhance antigen-specific CD8 + T-cell responses to HER-2 (4.5%; p < 0.005) and MUC-1 (19%; p < 0.05) tetramers. The mature DCs could elicit a robust and dose-dependent antigen-specific cytotoxic T-lymphocyte response (65%) which was tumoricidal to autologous breast cancer cells in vitro compared to T-lymphocytes that were primed with autologous lysate loaded-DCs (p < 0.005). Lastly, we showed that the mature DCs post-cryopreservation maintained high viability, maintained their mature phenotype, and remained free of endotoxins or mycoplasma. We have developed a DC vaccine that is cytotoxic to autologous breast cancer cells in vitro. The tools and technology generated here will now be applied to a phase I/IIa clinical trial.

Intracellular Delivery by Membrane Disruption: Mechanisms, Strategies, and Concepts

Intracellular delivery is a key step in biological research and has enabled decades of biomedical discoveries. It is also becoming increasingly important in industrial and medical applications ranging from biomanufacture to cell-based therapies. Here, we review techniques for membrane disruption-based intracellular delivery from 1911 until the present. These methods achieve rapid, direct, and universal delivery of almost any cargo molecule or material that can be dispersed in solution. We start by covering the motivations for intracellular delivery and the challenges associated with the different cargo types-small molecules, proteins/peptides, nucleic acids, synthetic nanomaterials, and large cargo. The review then presents a broad comparison of delivery strategies followed by an analysis of membrane disruption mechanisms and the biology of the cell response. We cover mechanical, electrical, thermal, optical, and chemical strategies of membrane disruption with a particular emphasis on their applications and challenges to implementation. Throughout, we highlight specific mechanisms of membrane disruption and suggest areas in need of further experimentation. We hope the concepts discussed in our review inspire scientists and engineers with further ideas to improve intracellular delivery.

Design and Development of Modified mRNA Encoding Core Antigen of Hepatitis C Virus: a Possible Application in Vaccine Production

Background:

Hepatitis C virus (HCV) is a blood-borne pathogen, resulting in liver cirrhosis and liver cancer. Despite of many efforts in development of treatments for HCV, no vaccine has been licensed yet. The purpose of this study was to design and prepare a specific mRNA, without 5’ cap and poly (A) tail transcribed in vitro capable of coding core protein and also to determine its functionality.

Methods:

Candidate mRNA was prepared by in vitro transcription of the designed construct consisting of 5’ and 3’ untranslated regions of heat shock proteins 70 (hsp70) mRNA, T7 promoter, internal ribosome entry site (IRES) sequences of eIF4G related to human dendritic cells (DCs), and the Core gene of HCV. To design the modified mRNA, the 5’ cap and poly (A) tail structures were not considered. DCs were transfected by in vitro-transcribed messenger RNA (IVT-mRNA) and the expressions of green fluorescent protein (GFP), and Core genes were determined by microscopic examination and Western blotting assay.

Results:

Cell transfection results showed that despite the absence of 5’ cap and poly (A) tail, the structure of the mRNA was stable. Moreover, the successful expressions of GFP and Core genes were achieved.

Conclusion:

Our findings indicated the effectiveness of a designed IVT-mRNA harboring the Core gene of HCV in transfecting and expressing the antigens in DCs. Considering the simple and efficient protocol for the preparation of this IVT-mRNA and its effectiveness in expressing the gene that it carries, this IVT-mRNA could be suitable for development of an RNA vaccine against HCV.

Use of cord blood derived T-cells in cancer immunotherapy: milestones achieved and future perspectives

INTRODUCTION

Hematopoietic cell transplantation is a potentially lifesaving procedure for patients with hematological malignancies who are refractory to conventional chemotherapy and/or irradiation treatment. Umbilical cord blood (CB) transplantation, as a hematopoietic stem and progenitor cell (HSPC) source, has several advantages over bone marrow transplantation with respect to matching and prompt availability for transplantation. Additionally, CB has some inherent features, such as rapid expansion of T cells, lower prevalence of graft-versus-host disease and higher graft versus tumor efficacy that make this HSPC cell source more favorable over other HSPC sources. Areas covered: This review summarizes the current CB and CB derived T cell applications aiming to better disease control for hematological malignancies and discusses future directions to more effective therapies. Expert commentary: CB transplantation could be used as a platform to extract cord blood derived T cells for ex vivo expansion and/or gene modification to improve cellular immunotherapies. In addition, combining cord blood gene-engineered T cell products with vaccination strategies, such as cord blood derived dendritic cell based vaccines, may provide synergistic immunotherapies with enhanced anti-tumor effects.

mRNA vaccines - a new era in vaccinology

mRNA vaccines represent a promising alternative to conventional vaccine approaches because of their high potency, capacity for rapid development and potential for low-cost manufacture and safe administration. However, their application has until recently been restricted by the instability and inefficient in vivo delivery of mRNA. Recent technological advances have now largely overcome these issues, and multiple mRNA vaccine platforms against infectious diseases and several types of cancer have demonstrated encouraging results in both animal models and humans. This Review provides a detailed overview of mRNA vaccines and considers future directions and challenges in advancing this promising vaccine platform to widespread therapeutic use.

Engineering WT1-Encoding mRNA to Increase Translational Efficiency in Dendritic Cells

Dendritic cells (DCs) are the orchestrators of the immune system and are frequently used in clinical trials in order to boost the immune system in cancer patients. Among several available techniques for DC modification, mRNA electroporation is an interesting technique due to the favorable characteristics of mRNA. Antigen expression level and duration can be increased by multiple optimizations of an antigen-encoding mRNA template. Here, we describe different molecular modifications to a WT1-encoding mRNA construct in order to increase antigen expression and the subsequent introduction of mRNA into DCs.

Novel immunotherapies for the treatment of melanoma

Immunotherapies are achieving clinical success for the treatment of many cancers. However, it has taken a long time to exploit the potential of the immune system for the treatment of human cancers. We cannot forget that this has been the consequence of very extensive work in basic research in preclinical models and in human patients. Thus, it is rather hard to compile all of it while giving a comprehensive view on this subject. Here we have attempted to give an overall perspective in immunotherapy of melanoma. A brief overview on current therapies is provided, followed by adoptive cell therapies. Gene engineering strategies to improve these therapies are also explained, finishing with therapies based on interference with immune checkpoint pathways.

Rethinking cancer nanotheranostics

Advances in nanoparticle synthesis and engineering have produced nanoscale agents affording both therapeutic and diagnostic functions that are often referred to by the portmanteau 'nanotheranostics'. The field is associated with many applications in the clinic, especially in cancer management. These include patient stratification, drug-release monitoring, imaging-guided focal therapy and post-treatment response monitoring. Recent advances in nanotheranostics have expanded this notion and enabled the characterization of individual tumours, the prediction of nanoparticle-tumour interactions, and the creation of tailor-designed nanomedicines for individualized treatment. Some of these applications require breaking the dogma that a nanotheranostic must combine both therapeutic and diagnostic agents within a single, physical entity; instead, it can be a general approach in which diagnosis and therapy are interwoven to solve clinical issues and improve treatment outcomes. In this Review, we describe the evolution and state of the art of cancer nanotheranostics, with an emphasis on clinical impact and translation.

Immunotherapy for the treatment of breast cancer

INTRODUCTION

Breast cancer is the most common cancer as well as the first cause of death by cancer in women worldwide. Although routine treatment improves the outcome of early stage breast cancer patients, there is no effective therapy for the disseminated disease. Immunotherapy has emerged as a powerful therapeutic strategy for the treatment of many cancers. Although traditionally conceived as a non-immunogenic tumor, breast cancer is now considered a potential target for immunotherapy. Areas covered: In this review, the authors discuss different immunotherapeutic strategies that are currently being tested for the treatment of breast cancer: These strategies include: (i) blockade of immunological checkpoints, (ii) antitumor vaccines, (iii) regulatory T cell blockade, (iv) adoptive T cell transfer therapy, (iv) adoptive immunotherapy with monoclonal antibodies, and (v) combination of immunotherapy with chemotherapy. Expert opinion: A growing body of evidence indicates that immunotherapeutic strategies can benefit a larger cohort of breast cancer patients than hitherto anticipated. Since breast tumors entail multiple mechanisms to impair antitumor immunity, the immunological characterization of individual tumors and the selection of suitable combinations of chemotherapeutic and immunotherapeutic approaches are required to achieve significant clinical benefit in these patients.

Efficient Nanovaccine Delivery in Cancer Immunotherapy

Vaccines hold tremendous potential for cancer immunotherapy by treating the immune system. Subunit vaccines, including molecular adjuvants and cancer-associated antigens or cancer-specific neoantigens, can elicit potent antitumor immunity. However, subunit vaccines have shown limited clinical benefit in cancer patients, which is in part attributed to inefficient vaccine delivery. In this Perspective, we discuss vaccine delivery by synthetic nanoparticles or naturally derived nanoparticles for cancer immunotherapy. Nanovaccines can efficiently codeliver adjuvants and multiepitope antigens into lymphoid organs and into antigen-presenting cells, and the intracellular release of vaccine and cross-presentation of antigens can be fine-tuned via nanovaccine engineering. Aside from peptide antigens, antigen-encoding mRNA for cancer immunotherapy delivered by nanovaccine will also be discussed.

Lipopolyplex potentiates anti-tumor immunity of mRNA-based vaccination

mRNA-based vaccines have the benefit of triggering robust anti-cancer immunity without the potential danger of genome integration from DNA vaccines or the limitation of antigen selection from peptide vaccines. Yet, a conventional mRNA vaccine comprising of condensed mRNA molecules in a positively charged protein core structure is not effectively internalized by the antigen-presenting cells. It cannot offer sufficient protection for mRNA molecules from degradation by plasma and tissue enzymes either. Here, we have developed a lipopolyplex mRNA vaccine that consists of a poly-(β-amino ester) polymer mRNA core encapsulated into a 1,2-dioleoyl-sn-glycero-3-ethylphosphocholine/1,2-dioleoyl-sn-glycero-3-phosphatidyl-ethanolamine/1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)-2000 (EDOPC/DOPE/DSPE-PEG) lipid shell. This core-shell structured mRNA vaccine enters dendritic cells through macropinocytosis. It displayed intrinsic adjuvant activity by potently stimulating interferon-β and interleukin-12 expression in dendritic cells through Toll-like receptor 7/8 signaling. Dendritic cells treated with the mRNA vaccine displayed enhanced antigen presentation capability. Mice bearing lung metastatic B16-OVA tumors expressing the ovalbumin antigen were treated with the lipopolyplex mRNA, and over 90% reduction of tumor nodules was observed. Collectively, this core-shell structure offers a promising platform for mRNA vaccine development.

Efficient Presentation of Multiple Endogenous Epitopes to Both CD4+ and CD8+ Diabetogenic T Cells for Tolerance

Antigen-specific immunotherapy of type 1 diabetes, typically via delivery of a single native β cell antigen, has had little clinical benefit to date. With increasing evidence that diabetogenic T cells react against multiple β cell antigens, including previously unappreciated neo-antigens that can be emulated by mimotopes, a shift from protein- to epitope-based therapy is warranted. To this end, we aimed to achieve efficient co-presentation of multiple major epitopes targeting both CD4⁺ and CD8⁺ diabetogenic T cells. We have compared native epitopes versus mimotopes as well as various targeting signals in an effort to optimize recognition by both types of T cells in vitro. Optimal engagement of all T cells was achieved with segregation of CD8 and CD4 epitopes, the latter containing mimotopes and driven by endosome-targeting signals, after delivery into either dendritic or stromal cells. The CD4⁺ T cell responses elicited by the endogenously delivered epitopes were comparable with high concentrations of soluble peptide and included functional regulatory T cells. This work has important implications for the improvement of antigen-specific therapies using an epitope-based approach to restore tolerance in type 1 diabetes and in a variety of other diseases requiring concomitant targeting of CD4⁺ and CD8⁺ T cells.

Signal transducer and activator of transcription 3 in myeloid-derived suppressor cells: an opportunity for cancer therapy

Cancer progression is in part determined by interactions between cancer cells and stromal cells in the tumor microenvironment (TME). The identification of cytotoxic tumor-infiltrating lymphocytes has instigated research into immune stimulating cancer therapies. Although a promising direction, immunosuppressive mechanisms exerted at the TME hamper its success. Myeloid-derived suppressor cells (MDSCs) have come to the forefront as stromal cells that orchestrate the immunosuppressive TME. Consequently, this heterogeneous cell population has been the object of investigation. Studies revealed that the transcription factor signal transducer and activator of transcription 3 (STAT3) largely dictates the recruitment, activation and function of MDSCs in the TME. Therefore, this review will focus on the role of this key transcription factor during the MDSC's life cycle and on the therapeutic opportunities it offers.

From the RNA world to the clinic

The study of RNA has continually emphasized the structural and functional versatility of RNA molecules. This versatility has inspired translational and clinical researchers to explore the utility of RNA-based therapeutic agents for a wide variety of medical applications. Several RNA therapeutics, with diverse modes of action, are being evaluated in large late-stage clinical trials, and many more are in early clinical development. Hundreds of patients are enrolled in large trials testing messenger RNAs to combat cancer, small interfering RNAs to treat renal and hepatic disorders, and aptamers to combat ocular and cardiovascular disease. Results from these studies are generating considerable interest among the biomedical community and the public and will be important for the future development of this emerging class of therapeutic agents.

Particle-mediated Intravenous Delivery of Antigen mRNA Results in Strong Antigen-specific T-cell Responses Despite the Induction of Type I Interferon

Cancer vaccines based on mRNA are extensively studied. The fragile nature of mRNA has instigated research into carriers that can protect it from ribonucleases and as such enable its systemic use. However, carrier-mediated delivery of mRNA has been linked to production of type I interferon (IFN) that was reported to compromise the effectiveness of mRNA vaccines. In this study, we evaluated a cationic lipid for encapsulation of mRNA. The nanometer-sized, negatively charged lipid mRNA particles (LMPs) efficiently transfected dendritic cells and macrophages in vitro. Furthermore, i.v. delivery of LMPs resulted in rapid expression of the mRNA-encoded protein in spleen and liver, predominantly in CD11c(+) cells and to a minor extent in CD11b(+) cells. Intravenous immunization of mice with LMPs containing ovalbumin, human papilloma virus E7, and tyrosinase-related protein-2 mRNA, either combined or separately, elicited strong antigen-specific T-cell responses. We further showed the production of type I IFNs upon i.v. LMP delivery. Although this decreased the expression of the mRNA-encoded protein, it supported the induction of antigen-specific T-cell responses. These data question the current notion that type I IFNs hamper particle-mediated mRNA vaccines.

mRNA Cancer Vaccines

mRNA cancer vaccines are a relatively new class of vaccines, which combine the potential of mRNA to encode for almost any protein with an excellent safety profile and a flexible production process. The most straightforward use of mRNA vaccines in oncologic settings is the immunization of patients with mRNA vaccines encoding tumor-associated antigens (TAAs). This is exemplified by the RNActive^® technology, which induces balanced humoral and cellular immune responses in animal models and is currently evaluated in several clinical trials for oncologic indications. A second application of mRNA vaccines is the production of personalized vaccines. This is possible because mRNA vaccines are produced by a generic process, which can be used to quickly produce mRNA vaccines targeting patient-specific neoantigens that are identified by analyzing the tumor exome. Apart from being used directly to vaccinate patients, mRNAs can also be used in cellular therapies to transfect patient-derived cells in vitro and infuse the manipulated cells back into the patient. One such application is the transfection of patient-derived dendritic cells (DCs) with mRNAs encoding TAAs, which leads to the presentation of TAA-derived peptides on the DCs and an activation of antigen-specific T cells in vivo. A second application is the transfection of patient-derived T cells with mRNAs encoding chimeric antigen receptors, which allows the T cells to directly recognize a specific antigen expressed on the tumor. In this chapter, we will review preclinical and clinical data for the different approaches.

Novel Treatments in Development for Melanoma

The past several years can be considered a renaissance era in the treatment of metastatic melanoma. Following a 30-year stretch in which oncologists barely put a dent in a very grim overall survival (OS) rate for these patients, things have rapidly changed course with the recent approval of three new melanoma drugs by the FDA. Both oncogene-targeted therapy and immune checkpoint blockade approaches have shown remarkable efficacy in a subset of melanoma patients and have clearly been game-changers in terms of clinical impact. However, most patients still succumb to their disease, and thus, there remains an urgent need to improve upon current therapies. Fortunately, innovations in molecular medicine have led to many silent gains that have greatly increased our understanding of the nature of cancer biology as well as the complex interactions between tumors and the immune system. They have also allowed for the first time a detailed understanding of an individual patient's cancer at the genomic and proteomic level. This information is now starting to be employed at all stages of cancer treatment, including diagnosis, choice of drug therapy, treatment monitoring, and analysis of resistance mechanisms upon recurrence. This new era of personalized medicine will foreseeably lead to paradigm shifts in immunotherapeutic treatment approaches such as individualized cancer vaccines and adoptive transfer of genetically modified T cells. Advances in xenograft technology will also allow for the testing of drug combinations using in vivo models, a truly necessary development as the number of new drugs needing to be tested is predicted to skyrocket in the coming years. This chapter will provide an overview of recent technological developments in cancer research, and how they are expected to impact future diagnosis, monitoring, and development of novel treatments for metastatic melanoma.