mRNA: A Versatile Molecule for Cancer Vaccines

In Vivo Delivery of Spherical and Cylindrical In Vitro Reconstituted Virus-like Particles Containing the Same Self-Amplifying mRNA

The dramatic effectiveness of recent mRNA (mRNA)-based COVID vaccines delivered in lipid nanoparticles has highlighted the promise of mRNA therapeutics in general. In this report, we extend our earlier work on self-amplifying mRNAs delivered in spherical in vitro reconstituted virus-like particles (VLPs), and on drug delivery using cylindrical virus particles. In particular, we carry out separate in vitro assemblies of a self-amplifying mRNA gene in two different virus-like particles: one spherical, formed with the capsid protein of cowpea chlorotic mottle virus (CCMV), and the other cylindrical, formed from the capsid protein of tobacco mosaic virus (TMV). The mRNA gene is rendered self-amplifying by genetically fusing it to the RNA-dependent RNA polymerase (RdRp) of Nodamura virus, and the relative efficacies of cell uptake and downstream protein expression resulting from their CCMV- and TMV-packaged forms are compared directly. This comparison is carried out by their transfections into cells in culture: expressions of two self-amplifying genes, enhanced yellow fluorescent protein (EYFP) and Renilla luciferase (Luc), packaged alternately in CCMV and TMV VLPs, are quantified by fluorescence and chemiluminescence levels, respectively, and relative numbers of the delivered mRNAs are measured by quantitative real-time PCR. The cellular uptake of both forms of these VLPs is further confirmed by confocal microscopy of transfected cells. Finally, VLP-mediated delivery of the self-amplifying-mRNA in mice following footpad injection is shown by in vivo fluorescence imaging to result in robust expression of EYFP in the draining lymph nodes, suggesting the potential of these plant virus-like particles as a promising mRNA gene and vaccine delivery modality. These results establish that both CCMV and TMV VLPs can deliver their in vitro packaged mRNA genes to immune cells and that their self-amplifying forms significantly enhance in situ expression. Choice of one VLP (CCMV or TMV) over the other will depend on which geometry of nucleocapsid is self-assembled more efficiently for a given length and sequence of RNA, and suggests that these plant VLP gene delivery systems will prove useful in a wide variety of medical applications, both preventive and therapeutic.

Recent advances in mRNA-based vaccine for cancer therapy; bench to bedside

The messenger RNA (mRNA) vaccines have progressed from a theoretical concept to a clinical reality over the last few decades. Compared to conventional vaccination methods, these vaccines have a number of benefits, such as substantial potency, rapid growth, inexpensive production, and safe administration. Nevertheless, their usefulness was restricted up to now due to worries about the erratic and ineffective circulation of mRNA in vivo. Thankfully, these worries have largely been allayed by recent technological developments, which have led to the creation of multiple mRNA vaccination platforms for cancer and viral infections. The mRNA vaccines have been demonstrated as a powerful alternative to traditional conventional vaccines because of their high potency, safety and efficacy, capacity for rapid clinical development, and potential for rapid, low-cost manufacturing. The paper will examine the present status of mRNA vaccine technology and suggest future paths for the advancement and application of this exciting vaccine platform as a common therapeutic choice.

PRDM16, Negatively Regulated by miR-372-3p, Suppresses Cell Proliferation and Invasion in Prostate Cancer

Prostate cancer (PCa) is one of the most prevalent malignant tumors. The alternation of microRNA (miRNA) expression is associated with prostate cancer progression, whereas its way to influence progression of prostate cancer remains elusive. The expression levels of PRDM16 mRNA and miR-372-3p in PCa cell lines were analyzed using qRT-PCR. The protein expression of PRDM16 in PCa cell lines was also analyzed using western blot. CCK-8, wound healing, and Transwell assays were applied to examine cell proliferation, migration, and invasion in prostate cancer cells, respectively. Dual-luciferase reporter assay was utilized to validate the interaction between miR-372-3p and PRDM16. In the present study, markedly decreased PRDM16 mRNA and protein expression levels were observed in prostate cancer cells. PRDM16 overexpression hampered cellular proliferation, migration, and invasion, while silencing PRDM16 had the opposite effect. Moreover, miR-372-3p could target the regulation expression of PRDM16. Rescue experiments demonstrated that upregulating miR-372-3p conspicuously restored the inhibitory effect of increased PRDM16 on cell proliferation, migration, and invasion in PCa. Overall, our study clarifies the biological role of miR-372-3p/PRDM16 axis in prostate cancer progression, which may be effective biomarkers for clinical treatment of prostate cancer.

RNA in Cancer Immunotherapy: Unlocking the Potential of the Immune System

Recent advances in the manufacturing, modification, purification, and cellular delivery of ribonucleic acid (RNA) have enabled the development of RNA-based therapeutics for a broad array of applications. The approval of two SARS-CoV-2-targeting mRNA-based vaccines has highlighted the advances of this technology. Offering rapid and straightforward manufacturing, clinical safety, and versatility, this paves the way for RNA therapeutics to expand into cancer immunotherapy. Together with ongoing trials on RNA cancer vaccination and cellular therapy, RNA therapeutics could be introduced into clinical practice, possibly stewarding future personalized approaches. In the present review, we discuss recent advances in RNA-based immuno-oncology together with an update on ongoing clinical applications and their current challenges.

PRDM16, negatively regulated by miR-372-3p, suppresses cell proliferation and invasion in prostate cancer

Prostate cancer (PCa) is one of the most prevalent malignant tumours. The alternation of microRNAs (miRNAs) expression is associated with prostate cancer progression, whereas its way to influence progression of prostate cancer remains elusive. The expression levels of PRDM16 mRNA and miR-372-3p in PCa cell lines were analysed using qRT-PCR. The protein expression of PRDM16 in PCa cell lines was also analysed using Western blot. CCK-8, wound healing and Transwell assays were applied to examine cell proliferation, migration, and invasion in prostate cancer cells, respectively. Dual-luciferase reporter assay was utilised to validate the interaction between miR-372-3p and PRDM16. In the present study, markedly decreased PRDM16 mRNA and protein expression levels were observed in prostate cancer cells. PRDM16 overexpression hampered cellular proliferation, migration, and invasion, while silencing PRDM16 had the opposite effect. Moreover, miR-372-3p could target the regulation expression of PRDM16. Rescue experiments demonstrated that upregulating miR-372-3p conspicuously restored the inhibitory effect of increased PRDM16 on cell proliferation, migration, and invasion in PCa. Overall, our study clarifies the biological role of miR-372-3p/PRDM16 axis in prostate cancer progression, which may be effective biomarkers for clinical treatment of prostate cancer.

The clinical progress of mRNA vaccines and immunotherapies

The emergency use authorizations (EUAs) of two mRNA-based severe acute respiratory syndrome coronavirus (SARS-CoV)-2 vaccines approximately 11 months after publication of the viral sequence highlights the transformative potential of this nucleic acid technology. Most clinical applications of mRNA to date have focused on vaccines for infectious disease and cancer for which low doses, low protein expression and local delivery can be effective because of the inherent immunostimulatory properties of some mRNA species and formulations. In addition, work on mRNA-encoded protein or cellular immunotherapies has also begun, for which minimal immune stimulation, high protein expression in target cells and tissues, and the need for repeated administration have led to additional manufacturing and formulation challenges for clinical translation. Building on this momentum, the past year has seen clinical progress with second-generation coronavirus disease 2019 (COVID-19) vaccines, Omicron-specific boosters and vaccines against seasonal influenza, Epstein-Barr virus, human immunodeficiency virus (HIV) and cancer. Here we review the clinical progress of mRNA therapy as well as provide an overview and future outlook of the transformative technology behind these mRNA-based drugs.

Potentialities and Challenges of mRNA Vaccine in Cancer Immunotherapy

Immunotherapy has become the breakthrough strategies for treatment of cancer in recent years. The application of messenger RNA in cancer immunotherapy is gaining tremendous popularity as mRNA can function as an effective vector for the delivery of therapeutic antibodies on immune targets. The high efficacy, decreased toxicity, rapid manufacturing and safe administration of mRNA vaccines have great advantages over conventional vaccines. The unprecedent success of mRNA vaccines against infection has proved its effectiveness. However, the instability and inefficient delivery of mRNA has cast a shadow on the wide application of this approach. In the past decades, modifications on mRNA structure and delivery methods have been made to solve these questions. This review summarizes recent advancements of mRNA vaccines in cancer immunotherapy and the existing challenges for its clinical application, providing insights on the future optimization of mRNA vaccines for the successful treatment of cancer.

Targeting nucleic acid-based therapeutics to tumors: Challenges and strategies for polyplexes

The current medical reality of cancer gene therapy is reflected by more than ten approved products on the global market, including oncolytic and other viral vectors and CAR T-cells as ex vivo gene-modified cell therapeutics. The development of synthetic antitumoral nucleic acid therapeutics has been proceeding at a lower but steady pace, fueled by a plethora of alternative nucleic acid platforms (from various antisense oligonucleotides, siRNA, microRNA, lncRNA, sgRNA, to larger mRNA and DNA) and several classes of physical and chemical delivery technologies. This review summarizes the challenges and strategies for tumor-targeted nucleic acid delivery. Focusing primarily on polyplexes (polycation complexes) as nanocarriers, delivery options across multiple barriers into tumor cells are illustrated.

Advances in Development of mRNA-Based Therapeutics

Recently, mRNA-based therapeutics have been greatly boosted since the development of novel technologies of both mRNA synthesis and delivery system. Promising results were showed in both preclinical and clinical studies in the field of cancer vaccine, tumor immunotherapy, infectious disease prevention and protein replacement therapy. Recent advancements in clinical trials also encouraged scientists to attempt new applications of mRNA therapy such as gene editing and cell programming. These studies bring mRNA therapeutics closer to real-world application. Herein, we provide an overview of recent advances in mRNA-based therapeutics.

A Changing World in Gene Therapy Research: Exciting Opportunities for Medical Advancement and Biosafety Challenges

Introduction: We previously reported on the United States' regulatory environment evolving to accommodate an emerging boom in gene therapy research. Several important developments have transpired in the 2 years since that article was published, including the coronavirus disease 2019 (COVID-19) pandemic and the drive for large-scale testing of vaccines containing recombinant or synthetic nucleic acid molecules. This report highlights key developments in the field with a focus on biosafety and issues of note to biosafety professionals with responsibilities over clinical research.

Discussion: We provide guidance for performing risk assessments on the currently approved gene therapy products as well as the most utilized types of investigational products in clinical trials. Areas of focus include the prominent approaches utilized in the three major areas of research: oncology, infectious diseases, and rare diseases.

Conclusion: The COVID-19 pandemic has created several opportunities for continued growth in gene therapy. National vaccination campaigns will result in greater public acceptance of gene therapy research. Technological advancements that made the vaccine race possible will spur the next generation of research. Advancements born in the developed world set the stage for the creation of therapeutics to treat greater numbers in the developing world and have the potential for massive benefits to global public health. Biosafety professionals and Institutional Biosafety Committees play key roles in contributing to the safe evidence-based advancement of gene therapy research. Biosafety professionals responsible for clinical research oversight must be aware of emerging technologies and their associated risks to support the safe and ethical conduct of research.

Therapeutic Targeting of Alternative RNA Splicing in Gastrointestinal Malignancies and Other Cancers

Recent comprehensive genomic studies including single-cell RNA sequencing and characterization have revealed multiple processes by which protein-coding and noncoding RNA processing are dysregulated in many cancers. More specifically, the abnormal regulation of mRNA and precursor mRNA (pre-mRNA) processing, which includes the removal of introns by splicing, is frequently altered in tumors, producing multiple different isoforms and diversifying protein expression. These alterations in RNA processing result in numerous cancer-specific mRNAs and pathogenically spliced events that generate altered levels of normal proteins or proteins with new functions, leading to the activation of oncogenes or the inactivation of tumor suppressor genes. Abnormally spliced pre-mRNAs are also associated with resistance to cancer treatment, and certain cancers are highly sensitive to the pharmacological inhibition of splicing. The discovery of these alterations in RNA processing has not only provided new insights into cancer pathogenesis but identified novel therapeutic vulnerabilities and therapeutic opportunities in targeting these aberrations in various ways (e.g., small molecules, splice-switching oligonucleotides (SSOs), and protein therapies) to modulate alternative RNA splicing or other RNA processing and modification mechanisms. Some of these strategies are currently progressing toward clinical development or are already in clinical trials. Additionally, tumor-specific neoantigens produced from these pathogenically spliced events and other abnormal RNA processes provide a potentially extensive source of tumor-specific therapeutic antigens (TAs) for targeted cancer immunotherapy. Moreover, a better understanding of the molecular mechanisms associated with aberrant RNA processes and the biological impact they play might provide insights into cancer initiation, progression, and metastasis. Our goal is to highlight key alternative RNA splicing and processing mechanisms and their roles in cancer pathophysiology as well as emerging therapeutic alternative splicing targets in cancer, particularly in gastrointestinal (GI) malignancies.

Small-scale manufacturing of neoantigen-encoding messenger RNA for early-phase clinical trials

Messenger RNA (mRNA) has become a promising tool in therapeutic cancer vaccine strategies. Owing to its flexible design and rapid production, mRNA is an attractive antigen delivery format for cancer vaccines targeting mutated peptides expressed in a tumor-the so-called neoantigens. These neoantigens are rarely shared between patients, and inclusion of these antigens in a vaccine requires the production of individual batches of patient-tailored mRNA. The authors have developed MIDRIX^NEO, a personalized mRNA-loaded dendritic cell vaccine targeting tumor neoantigens, which is currently being evaluated in a phase 1 clinical study in lung cancer patients. To facilitate this study, the authors set up a Good Manufacturing Practice (GMP)-compliant production process for the manufacture of small batches of personalized neoantigen-encoding mRNA. In this article, the authors describe the complete mRNA production process and the extensive quality assessment to which the mRNA is subjected. Validation runs have shown that the process delivers mRNA of reproducible, high quality. This process is now successfully applied for the production of neoantigen-encoding mRNA for the clinical evaluation of MIDRIX^NEO. To the authors' knowledge, this is the first time that a GMP-based production process of patient-tailored neoantigen mRNA has been described.

An Update on Self-Amplifying mRNA Vaccine Development

This review will explore the four major pillars required for design and development of an saRNA vaccine: Antigen design, vector design, non-viral delivery systems, and manufacturing (both saRNA and lipid nanoparticles (LNP)). We report on the major innovations, preclinical and clinical data reported in the last five years and will discuss future prospects.

Current State of the First COVID-19 Vaccines

SARS CoV-2 and its associated disease COVID-19 has devastated the world during 2020. Masks and social distancing could be efficient if done by large proportions of the population, but pandemic fatigue has decreased their efficacy. Economic shut downs come with large price tags and cannot be a long term solution either. The announcements by three vaccine manufacturers in November that their vaccines are 90% or more effective has given hope to at least those in the population who plan to get vaccinated as soon as a scientifically and medically sound vaccine becomes available. This review summarizes the underlying design strategies and current status of development of the nine vaccines that were in phase III trial on 8 November 2020. Contracts between vaccine manufacturing companies and governments aim at distributing the vaccine to a large part of the world population. Questions remain how the temperature sensitive mRNA vaccines will be transported and/or stored and how vaccination will be prioritized within each country. Additionally, current contracts do not cover all countries, with a serious gap in Africa and South America. The second part of this review will detail current distribution plans and remaining challenges with vaccine accessibility and acceptance.

A narrative review on the basic and clinical aspects of the novel SARS-CoV-2, the etiologic agent of COVID-19

The novel SARS-CoV-2 is responsible for causing the ongoing outbreak of coronavirus disease 19 (COVID-19), a systemic infection in humans. Ever since it was first detected in December 2019, the number of confirmed cases has continued to increase. Within a short period, this disease has become a global issue, and therefore it is characterized as a pandemic. The current understanding and explanations are based on epidemiological, clinical and physiological observations. Besides, it remains a great challenge, as much remains to be understood about this new disease-causing virus. Therefore, we seek to provide an overview of SARS-CoV-2, including its classification, origin, genomic structure, replication cycle, transmission, pathogenesis, clinical aspects, diagnosis, treatments, prevention and vaccine options. We conducted a literature search for the articles published up to August 2020 using the keywords ‘SAR-CoV-2’ and ‘COVID19’ in medical databases; PubMed, google scholar, EMBASE, and web of science. Based on the information collected, the emerging COVID-19, caused by SARS-CoV-2, exhibits strong infectivity but less virulence in terms of severity of disease and mortality rates in certain age groups. It inflicts more damage in terms of peoples’ health and well-being, social life, and global economic impacts. Unfortunately, there is no adequate global and standard response to this pandemic to date, and each country is facing a crisis based on its situation, expertise, and hypotheses. While there is no effective therapy and vaccine against the novel SARS-CoV-2 yet, preventive measures are the only tool available to our disposal to control the spread of the COVID-19 pandemic. Ongoing and future research is focused more on developing standard treatment strategies, and efficacious vaccines, which would be useful to tackle this pandemic globally.

Integration of gene profile to explore the hub genes of lung adenocarcinoma: A quasi-experimental study

BACKGROUND

Lung cancer is a leading cause of morbidity diseases worldwide, but the key mechanisms of lung cancer remain elusive. This study aims to integrate of GSE 118370 and GSE 32863 profile and identify the key genes and pathway involved in human lung adenocarcinoma.

METHODS

R software (RStudio, Version info: R 3.2.3, Forrester, USA) were utilized to find the differentially expressed genes. All the differentially expressed genes were analyzed by gene ontology, kyoto encyclopedia of genes and genomes. Protein-protein interaction networks were constructed by STRING database and analyzed by Cytohubber and Module. The cancer genome atlas database was used to verification the expression of hub genes. Quantitative reverse transcription-PCR was used to verify the bio-information results.

RESULTS

Sixty-four lung adenocarcinoma and 64 adjacent normal tissues were used for integration analysis. Five hundred ninety-nine co-expression genes were locked. Biological processes mainly enriched in angiogenesis. Cellular component focused on extracellular exosome and molecular function aimed on protein disulfide isomerase activity. Cytohubber analysis showed that GNG11, FPR2, P4HB, PIK3R1, CDC20, ADCY4, TIMP1, IL6, CXC chemokine ligand (CXCL)12, and GAS6 acted as the hub genes during lung adenocarcinoma. Module analysis presented Chemokine signaling pathway was a key pathway. Quantitative reverse transcription-PCR showed that the expression level of GNG11, FPR2, PIK3R1, ADCY4, IL6, CXCL12, and GAS6 were significantly decreased and P4HB, CDC20 and TIMP1 were increased in human adenocarcinoma tissues (P < .05). The cancer genome atlas online analysis showed GNG11 was not associated with survival.

CONCLUSIONS

This study firstly reported GNG11 acting as a hub gene in adenocarcinoma. GNG11 could be used as a biomarker for human adenocarcinoma. Chemokine signaling pathway might play important roles in lung adenocarcinoma.

COVID-19 in Human, Animal, and Environment: A Review

The medical authority in China, especially in Wuhan city, reported on December 2019 a large number of highly fatal, rapidly spreading viral pneumonia caused by an unknown coronavirus. The common history of all the patients was their visiting a Wuhan's whole food store, where live animals and seafood are sold. Irrespective of the efforts of the Chinese authorities, the virus spread rapidly all over the world by travelers, provoking widespread attention by the media and panic. Many previous coronavirus epidemics had been recorded, such as severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), and the recently newly discovered epidemic is named coronavirus disease of 2019 (COVID-19). This disease is caused by SARS Coronavirus-2 (SARS-CoV-2), and this virus is antigenically related to the SARS virus (SARS-CoV), which had been detected in 2002, depending on clinical, serological, and molecular findings. There is rapid competition among the researchers to discover the source of the virus, understand the mechanism of the disease development, establish treatment strategies, and determine the factors affecting the incidence of infection and severity of the disease, and focus on the production of a vaccine. Coronaviruses are a group of single-stranded, positive-sense RNA genome viruses; its genome length varies from 26 to 32 kb. Coronavirus causes mild to severe respiratory disorders. In December 2019, several cases of pneumonia of unknown causes were found in Wuhan city, which is located in the Hubei province in China. Chinese health authorities investigated the problem and found that a new virus caused such infection and, using next-generation sequencing, found the 2019 novel coronavirus (2019-nCoV). It has been transferred from humans to humans and animals to humans (zoonotic). Coronaviruses cause multiple respiratory problems, varying from common cold to severe infections such as SARS. General symptoms of infection include fatigue, cough, and breathing problems such as shortness of breath, as described by World Health Organization. Serious cases may result in pneumonia, renal failure, and even death. We address current information about the new SARS Coronavirus-2 as well as the COVID-19 disease caused by it in this review.

SARS-CoV-2 and Coronavirus Disease 2019: What We Know So Far

In December 2019, a cluster of fatal pneumonia cases presented in Wuhan, China. They were caused by a previously unknown coronavirus. All patients had been associated with the Wuhan Wholefood market, where seafood and live animals are sold. The virus spread rapidly and public health authorities in China initiated a containment effort. However, by that time, travelers had carried the virus to many countries, sparking memories of the previous coronavirus epidemics, severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), and causing widespread media attention and panic. Based on clinical criteria and available serological and molecular information, the new disease was called coronavirus disease of 2019 (COVID-19), and the novel coronavirus was called SARS Coronavirus-2 (SARS-CoV-2), emphasizing its close relationship to the 2002 SARS virus (SARS-CoV). The scientific community raced to uncover the origin of the virus, understand the pathogenesis of the disease, develop treatment options, define the risk factors, and work on vaccine development. Here we present a summary of current knowledge regarding the novel coronavirus and the disease it causes.

Therapeutic Vaccines for HPV-Associated Malignancies

Human papillomavirus (HPV)-related malignancies are responsible for almost all cases of cervical cancer in women, and over 50% of all cases of head and neck carcinoma. Worldwide, HPV-positive malignancies account for 4.5% of the global cancer burden, or over 600,000 cases per year. HPV infection is a pressing public health issue, as more than 80% of all individuals have been exposed to HPV by age 50, representing an important target for vaccine development to reduce the incidence of cancer and the economic cost of HPV-related health issues. The approval of Gardasil^® as a prophylactic vaccine for high-risk HPV 16 and 18 and low-risk HPV6 and 11 for people aged 11-26 in 2006, and of Cervarix^® in 2009, revolutionized the field and has since reduced HPV infection in young populations. Unfortunately, prophylactic vaccination does not induce immunity in those with established HPV infections or HPV-induced neoplasms, and there are currently no therapeutic HPV vaccines approved by the US Food and Drug Administration. This comprehensive review will detail the progress made in the development of therapeutic vaccines against high-risk HPV types, and potential combinations with other immunotherapeutic agents for more efficient and rational designs of combination treatments for HPV-associated malignancies.

Targeting mRNA processing as an anticancer strategy

Discoveries in the past decade have highlighted the potential of mRNA as a therapeutic target for cancer. Specifically, RNA sequencing revealed that, in addition to gene mutations, alterations in mRNA can contribute to the initiation and progression of cancer. Indeed, precursor mRNA processing, which includes the removal of introns by splicing and the formation of 3' ends by cleavage and polyadenylation, is frequently altered in tumours. These alterations result in numerous cancer-specific mRNAs that generate altered levels of normal proteins or proteins with new functions, leading to the activation of oncogenes or the inactivation of tumour-suppressor genes. Abnormally spliced and polyadenylated mRNAs are also associated with resistance to cancer treatment and, unexpectedly, certain cancers are highly sensitive to the pharmacological inhibition of splicing. This Review summarizes recent progress in our understanding of how splicing and polyadenylation are altered in cancer and highlights how this knowledge has been translated for drug discovery, resulting in the production of small molecules and oligonucleotides that modulate the spliceosome and are in clinical trials for the treatment of cancer.

Concise Review: Application of Chemically Modified mRNA in Cell Fate Conversion and Tissue Engineering

Chemically modified RNA (cmRNA) has potential as a safe and efficient tool for nucleic acid‐based therapies and regenerative medicine. Modifications in the chemistry of mRNA can enhance stability, reduce immunogenicity, and thus facilitate mRNA‐based nucleic acid therapy, which eliminates risk of insertional mutagenesis. In addition to these valuable advantages, the mRNA‐based method showed significantly higher efficacy for reprogramming somatic cells to pluripotency compared with DNA‐ or protein‐based methods. These findings suggest cmRNA can provide a powerful and safe tool for cell programming and reprogramming. Delivery methods, particularly using lipid nanoparticles, provide strategies for cell and organ‐specific targeting. The present study comprehensively compares studies that have used cmRNAs for cell fate conversion and tissue engineering. The information should be useful for investigators looking to choose the most efficient and straightforward cmRNA‐based strategy and protocol for tissue engineering and regenerative medicine research. stem cells translational medicine2019;8:833&843

Turning the corner on therapeutic cancer vaccines

Recent advances in several areas are rekindling interest and enabling progress in the development of therapeutic cancer vaccines. These advances have been made in target selection, vaccine technology, and methods for reversing the immunosuppressive mechanisms exploited by cancers. Studies testing different tumor antigens have revealed target properties that yield high tumor versus normal cell specificity and adequate immunogenicity to affect clinical efficacy. A few tumor-associated antigens, normal host proteins that are abnormally expressed in cancer cells, have been demonstrated to serve as good targets for immunotherapies, although many do not possess the needed specificity or immunogenicity. Neoantigens, which arise from mutated proteins in cancer cells, are truly cancer-specific and can be highly immunogenic, though the vast majority are unique to each patient's cancer and thus require development of personalized therapies. Lessons from previous cancer vaccine expeditions are teaching us the type and magnitude of immune responses needed, as well as vaccine technologies that can achieve these responses. For example, we are learning which vaccine approaches elicit the potent, balanced, and durable CD4 plus CD8 T cell expansion necessary for clinical efficacy. Exploration of interactions between the immune system and cancer has elucidated the adaptations that enable cancer cells to suppress and evade immune attack. This has led to breakthroughs in the development of new drugs, and, subsequently, to opportunities to combine these with cancer vaccines and dramatically increase patient responses. Here we review this recent progress, highlighting key steps that are bringing the promise of therapeutic cancer vaccines within reach.

Treatment with mRNA coding for the necroptosis mediator MLKL induces antitumor immunity directed against neo-epitopes

Cancer immunotherapy can induce durable antitumor responses. However, many patients poorly respond to such therapies. Here we describe a generic antitumor therapy that is based on the intratumor delivery of mRNA that codes for the necroptosis executioner mixed lineage kinase domain-like (MLKL) protein. This intervention stalls primary tumor growth and protects against distal and disseminated tumor formation in syngeneic mouse melanoma and colon carcinoma models. Moreover, MLKL-mRNA treatment combined with immune checkpoint blockade further improves the antitumor activity. MLKL-mRNA treatment rapidly induces T cell responses directed against tumor neo-antigens and requires CD4⁺ and CD8⁺ T cells to prevent tumor growth. Type I interferon signaling and Batf3-dependent dendritic cells are essential for this mRNA treatment to elicit tumor antigen-specific T cell responses. Moreover, MLKL-mRNA treatment blunts the growth of human lymphoma in mice with a reconstituted human adaptive immune system. MLKL-based treatment can thus be exploited as an effective antitumor immunotherapy.

Necroptosis has immunogenic cell death properties. Here, the authors show that the intra-tumor delivery of mRNA that codes for the necroptosis effector MLKL triggers neo-epitope-specific anti-tumor T cell responses and inhibits primary tumor growth and lung metastasis.

Modified ARCA analogs providing enhanced translational properties of capped mRNAs

Nowadays gene manipulation techniques ("DNA therapy") undergo progressive development and become widely used in industry and medicine. Since new advances in mRNA technologies are capable for obtaining particles with increased stability and translational efficiency, RNA become an attractive alternative for advancement of DNA therapy. For the past years studies have been conducted to explore different modification in mRNA cap structure and its effect on RNA properties. Recently we have shown that modification of the cap structure at the N2 position of 7-methylguanosine leads to an enhancement in translation inhibition. Currently, we have decided to exploit translational properties of mRNA capped with the ARCA (anti-reversed cap) analogs modified within N2 position of purine moiety s. We designed and synthesized three new dinucleotide cap analogs and investigated them in the rabbit reticulocyte lysate (RRL) and the human embryonic kidney derived HEK293 cell line, in vitro translational model systems. The obtained data indicate that, in both translational assays, the cap analogs synthesized by us when incorporated into mRNA improved its translational properties compared to the ARCA capped transcripts. Furthermore, the introduced modifications enhanced stability of the capped transcripts in HEK293 cells, which become higher compared to that of the transcripts capped with regular cap or with ARCA. Additionally one of the synthesized cap analogs revealed strong translation inhibition potency in RRL system, with IC₅₀ value 1.7 µM.

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.

Emergence of synthetic mRNA: In vitro synthesis of mRNA and its applications in regenerative medicine

The field of gene therapy has evolved over the past two decades after the first introduction of nucleic acid drugs, such as plasmid DNA (pDNA). With the development of in vitro transcription (IVT) methods, synthetic mRNA has become an emerging class of gene therapy. IVT mRNA has several advantages over conventional pDNA for the expression of target proteins. mRNA does not require nuclear localization to mediate protein translation. The intracellular process for protein expression is much simpler and there is no potential risk of insertion mutagenesis. Having these advantages, the level of protein expression is far enhanced as comparable to that of viral expression systems. This makes IVT mRNA a powerful alternative gene expression system for various applications in regenerative medicine. In this review, we highlight the synthesis and preparation of IVT mRNA and its therapeutic applications. The article includes the design and preparation of IVT mRNA, chemical modification of IVT mRNA, and therapeutic applications of IVT mRNA in cellular reprogramming, stem cell engineering, and protein replacement therapy. Finally, future perspectives and challenges of IVT mRNA are discussed.

The Potential and Challenges of Exploiting the Vast But Dynamic Neoepitope Landscape for Immunotherapy

Somatic non-synonymous mutations in the DNA of tumor cells may result in the presentation of tumor-specific peptides to T cells. The recognition of these so-called neoepitopes now has been firmly linked to the clinical success of checkpoint blockade and adoptive T cell therapy. Following proof-of-principle studies in preclinical models there was a surge of strategies to identify and exploit genetically defined clonally expressed neoepitopes. These approaches assume that neoepitope availability remains stable during tumor progression but tumor genetics has taught us otherwise. Under the pressure of the immune system, neoepitope expression dynamically evolves rendering neoepitope specific T cells ineffective. This implies that the immunotherapeutic strategy applied should be flexible in order to cope with these changes and/or aiming at a broad range of epitopes to prevent the development of escape variants. Here, we will address the heterogeneous and dynamic expression of neoepitopes and describe our perspective and demonstrate possibilities how to further exploit the clinical potential of the neoepitope repertoire.

Melatonin: does it have utility in the treatment of haematological neoplasms?

Melatonin, discovered in 1958 in the bovine pineal tissue, is an indoleamine that modulates circadian rhythms and has a wide variety of other functions. Haematological neoplasms are the leading cause of death in children and adolescents throughout the world. Research has demonstrated that melatonin is a low-toxicity protective molecule against experimental haematological neoplasms, but the mechanisms remain poorly defined. Here, we provide an introduction to haematological neoplasms and melatonin, especially as they relate to the actions of melatonin on haematological carcinogenesis. Secondly, we summarize what is known about the mechanisms of action of melatonin in the haematological system, including its pro-apoptotic, pro-oxidative, anti-proliferative and immunomodulatory actions. Thirdly, we discuss the advantages of melatonin in combination with other drugs against haematological malignancy, as well as its other benefits on the haematological system. Finally, we summarize the findings that are contrary to the suppressive effects of melatonin on cancers of haematological origin. We hope that this information will be helpful in the design of studies related to the therapeutic efficacy of melatonin in haematological neoplasms. LINKED ARTICLES: This article is part of a themed section on Recent Developments in Research of Melatonin and its Potential Therapeutic Applications. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.16/issuetoc.

Cationic Nanoliposomes Meet mRNA: Efficient Delivery of Modified mRNA Using Hemocompatible and Stable Vectors for Therapeutic Applications

Synthetically modified mRNA is a unique bioactive agent, ideal for use in therapeutic applications, such as cancer vaccination or treatment of single-gene disorders. In order to facilitate mRNA transfections for future therapeutic applications, there is a need for the delivery system to achieve optimal transfection efficacy, perform with durable stability, and provide drug safety. The objective of our study was to comprehensively analyze the use of 3β-[N-(N',N'-dimethylaminoethane) carbamoyl](DC-Cholesterol)/dioleoylphosphatidylethanolamine (DOPE) liposomes as a potential transfection agent for modified mRNAs. Our cationic liposomes facilitated a high degree of mRNA encapsulation and successful cell transfection efficiencies. More importantly, no negative effects on cell viability or immune reactions were detected posttransfection. Notably, the liposomes had a long-acting transfection effect on cells, resulting in a prolonged protein production of alpha-1-antitrypsin (AAT). In addition, the stability of these mRNA-loaded liposomes allowed storage for 80 days, without the loss of transfection efficacy. Finally, comprehensive analysis showed that these liposomes are fully hemocompatible with fresh human whole blood. In summary, we present an extensive analysis on the use of DC-cholesterol/DOPE liposomes as mRNA delivery vehicles. This approach provides the basis of a safe and efficient therapeutic strategy in the development of successful mRNA-based drugs.