mRNA-LNP vaccines tuned for systemic immunization induce strong antitumor immunity by engaging splenic immune cells

A novel LGALS1-depended and immune-associated fatty acid metabolism risk model in acute myeloid leukemia stem cells

Leukemia stem cells (LSCs) are recognized as the root cause of leukemia initiation, relapse, and drug resistance. Lipid species are highly abundant and essential component of human cells, which often changed in tumor microenvironment. LSCs remodel lipid metabolism to sustain the stemness. However, there is no useful lipid related biomarker has been approved for clinical practice in AML prediction and treatment. Here, we constructed and verified fatty acid metabolism-related risk score (LFMRS) model based on TCGA database via a series of bioinformatics analysis, univariate COX regression analysis, and multivariate COX regression analysis, and found that the LFMRS model could be an independent risk factor and predict the survival time of AML patients combined with age. Moreover, we revealed that Galectin-1 (LGALS1, the key gene of LFMRS) was highly expressed in LSCs and associated with poor prognosis of AML patients, and LGALS1 repression inhibited AML cell and LSC proliferation, enhanced cell apoptosis, and decreased lipid accumulation in vitro. LGALS1 repression curbed AML progression, lipid accumulation, and CD8+ T and NK cell counts in vivo. Our study sheds light on the roles of LFMRS (especially LGALS1) model in AML, and provides information that may help clinicians improve patient prognosis and develop personalized treatment regimens for AML.

Optimized lipid nanoparticles (LNPs) for organ-selective nucleic acids delivery in vivo

Nucleic acid therapeutics offer tremendous promise for addressing a wide range of common public health conditions. However, the in vivo nucleic acids delivery faces significant biological challenges. Lipid nanoparticles (LNPs) possess several advantages, such as simple preparation, high stability, efficient cellular uptake, endosome escape capabilities, etc., making them suitable for delivery vectors. However, the extensive hepatic accumulation of LNPs poses a challenge for successful development of LNPs-based nucleic acid therapeutics for extrahepatic diseases. To overcome this hurdle, researchers have been focusing on modifying the surface properties of LNPs to achieve precise delivery. The review aims to provide current insights into strategies for LNPs-based organ-selective nucleic acid delivery. In addition, it delves into the general design principles, targeting mechanisms, and clinical development of organ-selective LNPs. In conclusion, this review provides a comprehensive overview to provide guidance and valuable insights for further research and development of organ-selective nucleic acid delivery systems.

Emerging advances in delivery systems for mRNA cancer vaccines

The success of lipid nanoparticles (LNPs) in treating COVID-19 promotes further research of mRNA vaccines for cancer vaccination. Aiming at overcoming the constraints of currently available mRNA carriers, various alternative nano-vectors have been developed for delivering tumor antigen encoding mRNA and showed versatility to induce potent anti-tumor immunity. The rationally designed nano-vaccines increase the immune activation capacity of the mRNA vaccines by promoting crucial aspects including mRNA stability, cellular uptake, endosomal escape and targeting of immune cells or organs. Herein, we summarized the research progress of various mRNA based nano-vaccines that have been reported for cancer vaccination, including LNPs, lipid enveloped hybrid nanoparticles, polymeric nanoparticles etc. Several strategies that have been reported for further enhancing the immune stimulation efficacy of mRNA nano-vaccines, including developing nano-vaccines for co-delivering adjuvants, combination of immune checkpoint inhibitors, and optimizing the injection routes for boosting immune responses, have been reviewed. The progress of mRNA nano-vaccines in clinical trials and the prospect of the mRNA vaccines for cancer vaccination are also discussed.

Immunogenicity of Non-Mutated Ovarian Cancer-Specific Antigens

Epithelial ovarian cancer (EOC) has not significantly benefited from advances in immunotherapy, mainly because of the lack of well-defined actionable antigen targets. Using proteogenomic analyses of primary EOC tumors, we previously identified 91 aberrantly expressed tumor-specific antigens (TSAs) originating from unmutated genomic sequences. Most of these TSAs derive from non-exonic regions, and their expression results from cancer-specific epigenetic changes. The present study aimed to evaluate the immunogenicity of 48 TSAs selected according to two criteria: presentation by highly prevalent HLA allotypes and expression in a significant fraction of EOC tumors. Using targeted mass spectrometry analyses, we found that pulsing with synthetic TSA peptides leads to a high-level presentation on dendritic cells. TSA abundance correlated with the predicted binding affinity to the HLA allotype. We stimulated naïve CD8 T cells from healthy blood donors with TSA-pulsed dendritic cells and assessed their expansion with two assays: MHC-peptide tetramer staining and TCR Vβ CDR3 sequencing. We report that these TSAs can expand sizeable populations of CD8 T cells and, therefore, represent attractive targets for EOC immunotherapy.

The dawn of a new Era: mRNA vaccines in colorectal cancer immunotherapy

Colorectal cancer (CRC) is a typical cancer that accounts for 10% of all new cancer cases annually and nearly 10% of all cancer deaths. Despite significant progress in current classical interventions for CRC, these traditional strategies could be invasive and with numerous adverse effects. The poor prognosis of CRC patients highlights the evident and pressing need for more efficient and targeted treatment. Novel strategies regarding mRNA vaccines for anti-tumor therapy have also been well-developed since the successful application for the prevention of COVID-19. mRNA vaccine technology won the 2023 Nobel Prize in Physiology or Medicine, signaling a new direction in human anti-cancer treatment: mRNA medicine. As a promising new immunotherapy in CRC and other multiple cancer treatments, the mRNA vaccine has higher specificity, better efficacy, and fewer side effects than traditional strategies. The present review outlines the basics of mRNA vaccines and their advantages over other vaccines and informs an available strategy for developing efficient mRNA vaccines for CRC precise treatment. In the future, more exploration of mRNA vaccines for CRC shall be attached, fostering innovation to address existing limitations.

Cancer Nanovaccines: Nanomaterials and Clinical Perspectives

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

Therapeutic Vaccines for HPV-Associated Cervical Malignancies: A Systematic Review

IMPORTANCE

Despite widespread prophylactic vaccination, cervical cancer continues to be a major health problem with considerable mortality. Currently, therapeutic vaccines for HPV-associated cervical malignancies are being evaluated as a potential complement to the standard treatment.

OBJECTIVE

The present systematic review was conducted on randomized controlled trials (RCTs) to investigate the effects of therapeutic vaccines on the treatment of patients with cervical cancer and cervical intraepithelial neoplasia (CIN) of Grades 2 and 3.

EVIDENCE REVIEW

The PubMed, Embase, and Cochrane Central Register of Controlled Trials databases were searched. Only articles in English published up until 31 January 2024 were selected. Also, reference lists of the selected original papers and recent review articles were manually searched for additional sources. Data on study characteristics were extracted from the selected articles. Data on outcomes of interest were synthesized, and vaccine efficacy endpoints (histological lesion regression, clinical response, and overall survival) were selected as the basis for grouping the studies.

FINDINGS

After screening 831 articles, nine RCTs with 800 participants were included, of which seven studies with 677 participants involved CIN2 and CIN3 and examined lesion regression to ≤CIN1 as the efficacy endpoint. Results of two of these studies were deemed to have a high risk of bias, and another one did not contain statistical analyses. Results of the other four studies were quantitively synthesized, and the pooling of p-values revealed a significant difference between the vaccine and placebo groups in terms of lesion regression (p-values of 0.135, 0.049, and 0.034 in RCTs, yielding a combined p-value of 0.010). The certainty of the evidence was rated as moderate. Patients with advanced cervical cancers were studied in two RCTs with 123 participants. Clinical response and overall survival were taken as endpoints, and the results were reported as not significant. The certainty of the evidence of these results was rated as very low, mainly due to the very small number of events. All studies reported good tolerance for the vaccines.

CONCLUSIONS AND RELEVANCE

The results indicate the potential for therapeutic vaccines in the regression of CIN2 and CIN3 lesions. Moreover, a potential gap in evidence is identified regarding the very low number of RCTs in patients with advanced cervical cancer.

Has-miR-199a-3p/RELA/SCD inhibits immune checkpoints in AMD and promotes macrophage-mediated inflammation and pathological angiogenesis through lipid metabolism pathway: A computational analysis

More and more evidence shows that abnormal lipid metabolism leads to immune system dysfunction in AMD and promotes the occurrence of AMD by changing the homeostasis of ocular inflammation. However, the molecular mechanism underlying the effect of lipid metabolism on the phenotype and function of macrophages is still unclear, and the mechanism of association between AMD and cancer and COVID-19 has not been reported. The purpose of this study is to explore the interaction between lipid metabolism related genes, ferroptosis related genes and immunity in AMD, find out the key genes that affect the ferroptosis of AMD through lipid metabolism pathway and the molecular mechanism that mediates the action of macrophages, and find out the possible mechanism of lipid metabolism and potential co-therapeutic targets between AMD and cancer and COVID-19, so as to improve treatment decision-making and clinical results. For the first time, we have comprehensively analyzed the fatty acid molecule related genes, ferroptosis related genes and immune microenvironment of AMD patients, and determined that mast cells and M1 macrophages are the main causes of AMD inflammation, and found that SCD is the core gene in AMD that inhibits ferroptosis through lipid metabolism pathway, and verified the difference in the expression of SCD in AMD in a separate external data set. Based on the analysis of the mechanism of action of the SCD gene, we found for the first time that Has-miR-199a-3p/RELA/SCD is the core axis of action of lipid metabolism pathway to inhibit the ferroptosis of AMD. By inhibiting the immune checkpoint, we can enhance the immune cell activity of AMD and lead to the transformation of macrophages from M2 to M1, thereby promoting the inflammation and pathological angiogenesis of AMD. At the same time, we found that ACOX2 and PECR, as genes for fatty acid metabolism, may regulate the expression of SCD during the occurrence and development of COVID-19, thus affecting the occurrence and development of AMD. We found that FASD1 may be a key gene for the joint action of AMD and COVID-19, and SCD regulates the immune infiltration of macrophages in glioma and germ line tumors. In conclusion, our results can provide theoretical basis for the pathogenesis of AMD, help guide the treatment of AMD patients and their potentially related diseases and help to design effective drug targets.

Advances in Therapeutic Cancer Vaccines, Their Obstacles, and Prospects Toward Tumor Immunotherapy

Over the past few decades, cancer immunotherapy has experienced a significant revolution due to the advancements in immune checkpoint inhibitors (ICIs) and adoptive cell therapies (ACTs), along with their regulatory approvals. In recent times, there has been hope in the effectiveness of cancer vaccines for therapy as they have been able to stimulate de novo T-cell reactions against tumor antigens. These tumor antigens include both tumor-associated antigen (TAA) and tumor-specific antigen (TSA). Nevertheless, the constant quest to fully achieve these abilities persists. Therefore, this review offers a broad perspective on the existing status of cancer immunizations. Cancer vaccine design has been revolutionized due to the advancements made in antigen selection, the development of antigen delivery systems, and a deeper understanding of the strategic intricacies involved in effective antigen presentation. In addition, this review addresses the present condition of clinical tests and deliberates on their approaches, with a particular emphasis on the immunogenicity specific to tumors and the evaluation of effectiveness against tumors. Nevertheless, the ongoing clinical endeavors to create cancer vaccines have failed to produce remarkable clinical results as a result of substantial obstacles, such as the suppression of the tumor immune microenvironment, the identification of suitable candidates, the assessment of immune responses, and the acceleration of vaccine production. Hence, there are possibilities for the industry to overcome challenges and enhance patient results in the coming years. This can be achieved by recognizing the intricate nature of clinical issues and continuously working toward surpassing existing limitations.

CoPoP liposomes displaying stabilized clade C HIV-1 Env elicit tier 2 multiclade neutralization in rabbits

One of the strategies towards an effective HIV-1 vaccine is to elicit broadly neutralizing antibody responses that target the high HIV-1 Env diversity. Here, we present an HIV-1 vaccine candidate that consists of cobalt porphyrin-phospholipid (CoPoP) liposomes decorated with repaired and stabilized clade C HIV-1 Env trimers in a prefusion conformation. These particles exhibit high HIV-1 Env trimer decoration, serum stability and bind broadly neutralizing antibodies. Three sequential immunizations of female rabbits with CoPoP liposomes displaying a different clade C HIV-1 gp140 trimer at each dosing generate high HIV-1 Env-specific antibody responses. Additionally, serum neutralization is detectable against 18 of 20 multiclade tier 2 HIV-1 strains. Furthermore, the peak antibody titers induced by CoPoP liposomes can be recalled by subsequent heterologous immunization with Ad26-encoded membrane-bound stabilized Env antigens. Hence, a CoPoP liposome-based HIV-1 vaccine that can generate cross-clade neutralizing antibody immunity could potentially be a component of an efficacious HIV-1 vaccine.

Strategies for non-viral vectors targeting organs beyond the liver

In recent years, nanoparticles have evolved to a clinical modality to deliver diverse nucleic acids. Rising interest in nanomedicines comes from proven safety and efficacy profiles established by continuous efforts to optimize physicochemical properties and endosomal escape. However, despite their transformative impact on the pharmaceutical industry, the clinical use of non-viral nucleic acid delivery is limited to hepatic diseases and vaccines due to liver accumulation. Overcoming liver tropism of nanoparticles is vital to meet clinical needs in other organs. Understanding the anatomical structure and physiological features of various organs would help to identify potential strategies for fine-tuning nanoparticle characteristics. In this Review, we discuss the source of liver tropism of non-viral vectors, present a brief overview of biological structure, processes and barriers in select organs, highlight approaches available to reach non-liver targets, and discuss techniques to accelerate the discovery of non-hepatic therapies.

mRNA-LNP COVID-19 Vaccine Lipids Induce Complement Activation and Production of Proinflammatory Cytokines: Mechanisms, Effects of Complement Inhibitors, and Relevance to Adverse Reactions

A small fraction of people vaccinated with mRNA-lipid nanoparticle (mRNA-LNP)-based COVID-19 vaccines display acute or subacute inflammatory symptoms whose mechanism has not been clarified to date. To better understand the molecular mechanism of these adverse events (AEs), here, we analyzed in vitro the vaccine-induced induction and interrelations of the following two major inflammatory processes: complement (C) activation and release of proinflammatory cytokines. Incubation of Pfizer-BioNTech's Comirnaty and Moderna's Spikevax with 75% human serum led to significant increases in C5a, sC5b-9, and Bb but not C4d, indicating C activation mainly via the alternative pathway. Control PEGylated liposomes (Doxebo) also induced C activation, but, on a weight basis, it was ~5 times less effective than that of Comirnaty. Viral or synthetic naked mRNAs had no C-activating effects. In peripheral blood mononuclear cell (PBMC) cultures supplemented with 20% autologous serum, besides C activation, Comirnaty induced the secretion of proinflammatory cytokines in the following order: IL-1α < IFN-γ < IL-1β < TNF-α < IL-6 < IL-8. Heat-inactivation of C in serum prevented a rise in IL-1α, IL-1β, and TNF-α, suggesting C-dependence of these cytokines' induction, although the C5 blocker Soliris and C1 inhibitor Berinert, which effectively inhibited C activation in both systems, did not suppress the release of any cytokines. These findings suggest that the inflammatory AEs of mRNA-LNP vaccines are due, at least in part, to stimulation of both arms of the innate immune system, whereupon C activation may be causally involved in the induction of some, but not all, inflammatory cytokines. Thus, the pharmacological attenuation of inflammatory AEs may not be achieved via monotherapy with the tested C inhibitors; efficacy may require combination therapy with different C inhibitors and/or other anti-inflammatory agents.

Exploring blood lipids-immunity associations following HBV vaccination: evidence from a large cross-sectional study

Introduction

Serological responses following hepatitis B vaccination are crucial for preventing hepatitis B (HBV). However, the potential relationship between serum lipid levels and immunity from HBV vaccination remains poorly understood.

Methods

In this study, we conducted an analysis of the National Health and Nutrition Examination Survey (NHANES) data spanning from 2003 to 2016. Multivariable weighted logistic regression models, generalized linear analysis, stratified models, smooth curve fitting, segmentation effect analysis and sensitivity analysis were utilized to assess the relationships.

Results

After adjusting for relevant covariates, we observed that low levels of high-density lipoprotein cholesterol (HDL) were independently linked to a significantly lower seroprotective rate. Compared to HDL levels of ≥ 60 mg/dL, the odds ratios (ORs) for individuals with borderline levels (40-59 mg/dL for men, 50-59 mg/dL for women) and low levels (< 40 mg/dL for men, < 50 mg/dL for women) were 0.83 (95% CI 0.69-0.99) and 0.65 (95% CI 0.56-0.78), respectively. This association was particularly pronounced in individuals aged 40 or older. Conversely, higher levels of the triglyceride to HDL (TG/HDL) ratio (OR, 0.90; 95% CI, 0.84-0.98), total cholesterol to HDL (Chol/HDL) ratio (OR, 0.77; 95% CI, 0.64-0.92), and low-density lipoprotein to HDL (LDL/HDL) ratio (OR, 0.85; 95% CI, 0.76-0.96) were associated with a decreased likelihood of seroprotection.

Conclusion

This study suggests that lipid levels may play a role in modulating the immune response following HBV vaccination.

mRNA delivery systems for cancer immunotherapy: Lipid nanoparticles and beyond

mRNA-based vaccines are emerging as a promising alternative to standard cancer treatments and the conventional vaccines. Moreover, the FDA-approval of three nucleic acid based therapeutics (Onpattro, BNT162b2 and mRNA-1273) has further increased the interest and trust on this type of therapeutics. In order to achieve a significant therapeutic efficacy, the mRNA needs from a drug delivery system. In the last years, several delivery platforms have been explored, being the lipid nanoparticles (LNPs) the most well characterized and studied. A better understanding on how mRNA-based therapeutics operate (both the mRNA itself and the drug delivery system) will help to further improve their efficacy and safety. In this review, we will provide an overview of what mRNA cancer vaccines are and their mode of action and we will highlight the advantages and challenges of the different delivery platforms that are under investigation.

Lipid Nanoparticle-Based Delivery System-A Competing Place for mRNA Vaccines

mRNA, as one of the foci of biomedical research in the past decade, has become a candidate vaccine solution for various infectious diseases and tumors and for regenerative medicine and immunotherapy due to its high efficiency, safety, and effectiveness. A stable and effective delivery system is needed to protect mRNAs from nuclease degradation while also enhancing immunogenicity. The success of mRNA lipid nanoparticles in treating COVID-19, to a certain extent, marks a milestone for mRNA vaccines and also promotes further research on mRNA delivery systems. Here, we explore mRNA vaccine delivery systems, especially lipid nanoparticles (LNPs), considering the current research status, prospects, and challenges of lipid nanoparticles, and explore other mRNA delivery systems.

Lipid Nanoparticle (LNP) Delivery Carrier-Assisted Targeted Controlled Release mRNA Vaccines in Tumor Immunity

In recent years, lipid nanoparticles (LNPs) have attracted extensive attention in tumor immunotherapy. Targeting immune cells in cancer therapy has become a strategy of great research interest. mRNA vaccines are a potential choice for tumor immunotherapy, due to their ability to directly encode antigen proteins and stimulate a strong immune response. However, the mode of delivery and lack of stability of mRNA are key issues limiting its application. LNPs are an excellent mRNA delivery carrier, and their structural stability and biocompatibility make them an effective means for delivering mRNA to specific targets. This study summarizes the research progress in LNP delivery carrier-assisted targeted controlled release mRNA vaccines in tumor immunity. The role of LNPs in improving mRNA stability, immunogenicity, and targeting is discussed. This review aims to systematically summarize the latest research progress in LNP delivery carrier-assisted targeted controlled release mRNA vaccines in tumor immunity to provide new ideas and strategies for tumor immunotherapy, as well as to provide more effective treatment plans for patients.

An inoculation site-retained mRNA vaccine induces robust immune responses against SARS-CoV-2 variants

mRNA-based vaccines and therapeutic agents hold great promise in prevention and treatment of human diseases, yet high percentage of systemic adverse effect in clinic remains a big safety concern. One major potential cause is a high level of leakage of the locally inoculated mRNA vaccine nanoparticles into circulation. We have screened and optimized a core-shell structured lipopolyplex (LPP) formulation for mRNA with a tissue-retention property. Upon intramuscular inoculation, the mRNA-encapsulated LPP nanoparticles were preferentially taken up by the phagocytic antigen-presentation cells, and potently promoted dendritic cell maturation. We applied the new formulation to prepare a prophylactic vaccine for SARS-CoV-2, and observed potent humoral and cellular immune responses from the vaccine in both murine models and non-human primates. More importantly, the vaccine demonstrated a benign safety profile in non-human primates, with limited side effects after repeated treatment with high dosages of LPP/mRNA. Taken together, the inoculation site-retained vaccine formulation serves as a promising vehicle for mRNA vaccines and therapeutic agents.

Delivery of mRNA Vaccine with 1, 2-Diesters-Derived Lipids Elicits Fast Liver Clearance for Safe and Effective Cancer Immunotherapy

Messenger RNA (mRNA) vaccine is explored as a promising strategy for cancer immunotherapy, but the side effects, especially the liver-related damage caused by LNP, raise concerns about its safety. In this study, a novel library of 248 ionizable lipids comprising 1,2-diesters is designed via a two-step process involving the epoxide ring-opening reaction with carboxyl group-containing alkyl chains followed by an esterification reaction with the tertiary amines. Owing to the special chemical structure of 1,2-diesters, the top-performing lipids and formulations exhibit a faster clearance rate in the liver, contributing to increased stability and higher safety compared with DLin-MC3-DMA. Moreover, the LNP shows superior intramuscular mRNA delivery and elicits robust antigen-specific immune activation. The vaccinations delivered by the LNP system suppress tumor growth and prolong survival in both model human papillomavirus E7 and ovalbumin antigen-expressing tumor models. Finally, the structure of lipids which enhances the protein expression in the spleen and draining lymph nodes compared with ALC-0315 lipid in Comirnaty is further optimized. In conclusion, the 1, 2-diester-derived lipids exhibit rapid liver clearance and effective anticancer efficiency to different types of antigens-expressing tumor models, which may be a safe and universal platform for mRNA vaccines.

The Effect of Cholesterol Content on the Adjuvant Activity of Nucleic-Acid-Free Lipid Nanoparticles

RNA vaccines are applicable to the treatment of various infectious diseases via the inducement of robust immune responses against target antigens by expressing antigen proteins in the human body. The delivery of messenger RNA by lipid nanoparticles (LNPs) has become a versatile drug delivery system used in the administration of RNA vaccines. LNPs are widely considered to possess adjuvant activity that induces a strong immune response. However, the properties of LNPs that contribute to their adjuvant activity continue to require clarification. To characterize the relationships between the lipid composition, particle morphology, and adjuvant activity of LNPs, the nanostructures of LNPs and their antibody production were evaluated. To simply compare the adjuvant activity of LNPs, empty LNPs were subcutaneously injected with recombinant proteins. Consistent with previous research, the presence of ionizable lipids was one of the determinant factors. Adjuvant activity was induced when a tiny cholesterol assembly (cholesterol-induced phase, ChiP) was formed according to the amount of cholesterol present. Moreover, adjuvant activity was diminished when the content of cholesterol was excessive. Thus, it is plausible that an intermediate structure of cholesterol (not in a crystalline-like state) in an intra-particle space could be closely related to the immunogenicity of LNPs.

Morphological Characterization of Self-Amplifying mRNA Lipid Nanoparticles

The mRNA technology has emerged as a rapid modality to develop vaccines during pandemic situations with the potential to protect against endemic diseases. The success of mRNA in producing an antigen is dependent on the ability to deliver mRNA to the cells using a vehicle, which typically consists of a lipid nanoparticle (LNP). Self-amplifying mRNA (SAM) is a synthetic mRNA platform that, besides encoding for the antigen of interest, includes the replication machinery for mRNA amplification in the cells. Thus, SAM can generate many antigen encoding mRNA copies and prolong expression of the antigen with lower doses than those required for conventional mRNA. This work describes the morphology of LNPs containing encapsulated SAM (SAM LNPs), with SAM being three to four times larger than conventional mRNA. We show evidence that SAM changes its conformational structure when encapsulated in LNPs, becoming more compact than the free SAM form. A characteristic "bleb" structure is observed in SAM LNPs, which consists of a lipid-rich core and an aqueous RNA-rich core, both surrounded by a DSPC-rich lipid shell. We used SANS and SAXS data to confirm that the prevalent morphology of the LNP consists of two-core compartments where components are heterogeneously distributed between the two cores and the shell. A capped cylinder core-shell model with two interior compartments was built to capture the overall morphology of the LNP. These findings provide evidence that bleb two-compartment structures can be a representative morphology in SAM LNPs and highlight the need for additional studies that elucidate the role of spherical and bleb morphologies, their mechanisms of formation, and the parameters that lead to a particular morphology for a rational design of LNPs for mRNA delivery.

Considerations on the Design of Lipid-based mRNA Vaccines Against Cancer

Throughout the last decades, mRNA vaccines have been developed as a cancer immunotherapeutic and the technology recently gained momentum during the COVID-19 pandemic. Recent promising results obtained from clinical trials investigating lipid-based mRNA vaccines in cancer therapy further highlighted the potential of this therapy. Interestingly, while the technologies being used in authorized mRNA vaccines for the prevention of COVID-19 are relatively similar, mRNA vaccines in clinical development for cancer vaccination show marked differences in mRNA modification, lipid carrier, and administration route. In this review, we describe findings on how these factors can impact the potency of mRNA vaccines in cancer therapy and provide insights into the complex interplay between them. We discuss how lipid carrier composition can affect passive targeting to immune cells to improve the efficacy and safety of mRNA vaccines. Finally, we summarize strategies that are established or still being explored to improve the efficacy of mRNA cancer vaccines and include next-generation vaccines that are on the horizon in clinical development.

Lipoamino bundle LNPs for efficient mRNA transfection of dendritic cells and macrophages show high spleen selectivity

Messenger RNA (mRNA) is a powerful tool for nucleic acid-based therapies and vaccination, but efficient and specific delivery to target tissues remains a significant challenge. In this study, we demonstrate lipoamino xenopeptide carriers as components of highly efficient mRNA LNPs. These lipo-xenopeptides are defined as 2D sequences in different 3D topologies (bundles or different U-shapes). The polar artificial amino acid tetraethylene pentamino succinic acid (Stp) and various lipophilic tertiary lipoamino fatty acids (LAFs) act as ionizable amphiphilic units, connected in different ratios via bisamidated lysines as branching units. A series of more lipophilic LAF4-Stp1 carriers with bundle topology is especially well suited for efficient encapsulation of mRNA into LNPs, facilitated cellular uptake and strongly enhanced endosomal escape. These LNPs display improved, faster transfection kinetics compared to standard LNP formulations, with high potency in a variety of tumor cell lines (including N2a neuroblastoma, HepG2 and Huh7 hepatocellular, and HeLa cervical carcinoma cells), J774A.1 macrophages, and DC2.4 dendritic cells. High transfection levels were obtained even in the presence of serum at very low sub-microgram mRNA doses. Upon intravenous application of only 3 µg mRNA per mouse, in vivo mRNA expression is found with a high selectivity for dendritic cells and macrophages, resulting in a particularly high overall preferred expression in the spleen.

Biodistribution of RNA Vaccines and of Their Products: Evidence from Human and Animal Studies

Explosive developments in mRNA vaccine technology in the last decade have made it possible to achieve great success in clinical trials of mRNA vaccines to prevent infectious diseases and develop cancer treatments and mRNA-based gene therapy products. The approval of the mRNA-1273 and BNT162b2 mRNA vaccines against SARS-CoV-2 by the U.S. Food and Drug Administration has led to mass vaccination (with mRNA vaccines) of several hundred million people around the world, including children. Despite its effectiveness in the fight against COVID-19, rare adverse effects of the vaccination have been shown in some studies, including vascular microcirculation disorders and autoimmune and allergic reactions. The biodistribution of mRNA vaccines remains one of the most poorly investigated topics. This mini-review discussed the results of recent experimental studies on humans and rodents regarding the biodistribution of mRNA vaccines, their constituents (mRNA and lipid nanoparticles), and their encoded antigens. We focused on the dynamics of the biodistribution of mRNA vaccine products and on the possibility of crossing the blood-brain and blood-placental barriers as well as transmission to infants through breast milk. In addition, we critically assessed the strengths and weaknesses of the detection methods that have been applied in these articles, whose results' reliability is becoming a subject of debate.

Targeting cancer with mRNA-lipid nanoparticles: key considerations and future prospects

Harnessing mRNA-lipid nanoparticles (LNPs) to treat patients with cancer has been an ongoing research area that started before these versatile nanoparticles were successfully used as COVID-19 vaccines. Currently, efforts are underway to harness this platform for oncology therapeutics, mainly focusing on cancer vaccines targeting multiple neoantigens or direct intratumoural injections of mRNA-LNPs encoding pro-inflammatory cytokines. In this Review, we describe the opportunities of using mRNA-LNPs in oncology applications and discuss the challenges for successfully translating the findings of preclinical studies of these nanoparticles into the clinic. We critically appraise the potential of various mRNA-LNP targeting and delivery strategies, considering physiological, technological and manufacturing challenges. We explore these approaches in the context of the potential clinical applications best suited to each approach and highlight the obstacles that currently need to be addressed to achieve these applications. Finally, we provide insights from preclinical and clinical studies that are leading to this powerful platform being considered the next frontier in oncology treatment.

mRNA Cancer Vaccines: Construction and Boosting Strategies

In late 2020, the U.S. Food and Drug Administration (FDA) approved a lipid-based mRNA vaccine for the prevention of COVID-19, which has pushed this field to be more closely studied and motivated researchers to delve deeper into mRNA therapeutics. To date, the research on mRNA cancer vaccines has been developed rapidly, and substantial hopeful therapeutic results have been achieved against various solid tumors in clinical trials. In this review, we first introduce three main components of mRNA cancer vaccines, including mRNA antigens, adjuvants, and delivery vectors. Engineering these components can optimize the therapeutic effects of mRNA cancer vaccines. For instance, appropriate modification of mRNA structure can alleviate the poor stability and innate immunogenicity of mRNA, and the use of mRNA delivery vectors can address the issues of low delivery efficiency in vivo. Second, we emphatically discuss some strategies to further improve the efficacy of mRNA cancer vaccines, namely modulating the immunosuppressive tumor environment, optimizing administration routes, achieving targeting delivery to intended tissues or organs, and employing combination therapy. These strategies can strengthen the tumor inhibitory ability of mRNA cancer vaccines and increase the possibility of tumor elimination. Finally, we point out some challenges in the clinical practice of mRNA cancer vaccines and offer our perspectives on future developments in this rapidly evolving field. It is anticipated that mRNA cancer vaccines will be rapidly developed for clinical cancer therapy in the near future.

Quality by Design (QbD) and Design of Experiments (DOE) as a Strategy for Tuning Lipid Nanoparticle Formulations for RNA Delivery

The successful development of nonviral delivery systems for nucleic acids has been reported extensively over the past years. Increasingly employed to improve the delivery efficiency and therapeutic efficacy of RNA are lipid nanoparticles (LNPs). Many of the various critical formulation parameters can affect the quality attributes and effectiveness of these nano-formulations. Therefore, the systematic drug development approach (QbD) and multivariate design and statistical analysis (DOE) can be very helpful and recommended for the optimization of the composition and production of RNA-LNPs. This review addresses the concepts and applications of QbD and/or DOE for the development of lipid nanoparticles for the delivery of different types of RNA, reporting examples published in the ten recent years presenting the latest trends and regulatory requirements as well as the modern mathematical and statistical design methods. As the topic explored in this review is a novel approach, the full QbD has been described in only a few papers, and a few refer only to some aspects of QbD. In contrast, the DOE approach has been used in most of the optimization works. Different approaches and innovations in DOE have been observed. Traditional statistical tests and modeling (ANOVA, regression analysis) are slowly being replaced by artificial intelligence and machine learning methods.

Four Ounces Can Move a Thousand Pounds: The Enormous Value of Nanomaterials in Tumor Immunotherapy

The application of nanomaterials in healthcare has emerged as a promising strategy due to their unique structural diversity, surface properties, and compositional diversity. In particular, nanomaterials have found a significant role in improving drug delivery and inhibiting the growth and metastasis of tumor cells. Moreover, recent studies have highlighted their potential in modulating the tumor microenvironment (TME) and enhancing the activity of immune cells to improve tumor therapy efficacy. Various types of nanomaterials are currently utilized as drug carriers, immunosuppressants, immune activators, immunoassay reagents, and more for tumor immunotherapy. Necessarily, nanomaterials used for tumor immunotherapy can be grouped into two categories: organic and inorganic nanomaterials. Though both have shown the ability to achieve the purpose of tumor immunotherapy, their composition and structural properties result in differences in their mechanisms and modes of action. Organic nanomaterials can be further divided into organic polymers, cell membranes, nanoemulsion-modified, and hydrogel forms. At the same time, inorganic nanomaterials can be broadly classified as nonmetallic and metallic nanomaterials. The current work aims to explore the mechanisms of action of these different types of nanomaterials and their prospects for promoting tumor immunotherapy.

The Dual Role of the Innate Immune System in the Effectiveness of mRNA Therapeutics

Advances in molecular biology have revolutionized the use of messenger RNA (mRNA) as a therapeutic. The concept of nucleic acid therapy with mRNA originated in 1990 when Wolff et al. reported successful expression of proteins in target organs by direct injection of either plasmid DNA or mRNA. It took decades to bring the transfection efficiency of mRNA closer to that of DNA. The next few decades were dedicated to turning in vitro-transcribed (IVT) mRNA from a promising delivery tool for gene therapy into a full-blown therapeutic modality, which changed the biotech market rapidly. Hundreds of clinical trials are currently underway using mRNA for prophylaxis and therapy of infectious diseases and cancers, in regenerative medicine, and genome editing. The potential of IVT mRNA to induce an innate immune response favors its use for vaccination and immunotherapy. Nonetheless, in non-immunotherapy applications, the intrinsic immunostimulatory activity of mRNA directly hinders the desired therapeutic effect since it can seriously impair the target protein expression. Targeting the same innate immune factors can increase the effectiveness of mRNA therapeutics for some indications and decrease it for others, and vice versa. The review aims to present the innate immunity-related 'barriers' or 'springboards' that may affect the development of immunotherapies and non-immunotherapy applications of mRNA medicines.

Immunogenicity of lipid nanoparticles and its impact on the efficacy of mRNA vaccines and therapeutics

Several studies have utilized a lipid nanoparticle delivery system to enhance the effectiveness of mRNA therapeutics and vaccines. However, these nanoparticles are recognized as foreign materials by the body and stimulate innate immunity, which in turn impacts adaptive immunity. Therefore, it is crucial to understand the specific type of innate immune response triggered by lipid nanoparticles. This article provides an overview of the immunological response in the body, explores how lipid nanoparticles activate the innate immune system, and examines the adverse effects and immunogenicity-related development pathways associated with these nanoparticles. Finally, we highlight and explore strategies for regulating the immunogenicity of lipid nanoparticles.

mRNA-LNP vaccination-based immunotherapy augments CD8+ T cell responses against HPV-positive oropharyngeal cancer

Although mRNA vaccines are known as potent activators of antigen-specific immune responses against infectious diseases, limited understanding of how they drive the functional commitment of CD8+ T cells in tumor microenvironment (TME) and secondary lymphoid organs hinders their broader application in cancer immunotherapy. Here, we systematically evaluated the immunological effects of a lipid nanoparticle (LNP)-encapsulated mRNA vaccine that encodes human papillomavirus E7 protein (HPV mRNA-LNP), a tumor-specific antigen of HPV-positive oropharyngeal squamous cell carcinoma (OPSCC). HPV mRNA-LNP vaccination activated overall and HPV-specific CD8+ T cells, as well as differentially drove the functional commitment of CD8+ T cells through distinct IFN-response and exhaustion trajectories in the spleen and TME, respectively. Combination therapies of HPV mRNA-LNP vaccination with immune checkpoint blockades boosted HPV-specific CD8+ T cells while maintaining their anti-tumor function, thus further promoting tumor regression. Our results showed that the HPV mRNA-LNP vaccination combined with immune checkpoint blockade is a promising approach for immunotherapy of HPV-positive OPSCC.

mRNA nanodelivery systems: targeting strategies and administration routes

With the great success of coronavirus disease (COVID-19) messenger ribonucleic acid (mRNA) vaccines, mRNA therapeutics have gained significant momentum for the prevention and treatment of various refractory diseases. To function efficiently in vivo and overcome clinical limitations, mRNA demands safe and stable vectors and a reasonable administration route, bypassing multiple biological barriers and achieving organ-specific targeted delivery of mRNA. Nanoparticle (NP)-based delivery systems representing leading vector approaches ensure the successful intracellular delivery of mRNA to the target organ. In this review, chemical modifications of mRNA and various types of advanced mRNA NPs, including lipid NPs and polymers are summarized. The importance of passive targeting, especially endogenous targeting, and active targeting in mRNA nano-delivery is emphasized, and different cellular endocytic mechanisms are discussed. Most importantly, based on the above content and the physiological structure characteristics of various organs in vivo, the design strategies of mRNA NPs targeting different organs and cells are classified and discussed. Furthermore, the influence of administration routes on targeting design is highlighted. Finally, an outlook on the remaining challenges and future development toward mRNA targeted therapies and precision medicine is provided.

Tolerogenic Lipid Nanoparticles for Delivering Self-Antigen mRNA for the Treatment of Experimental Autoimmune Encephalomyelitis

Multiple sclerosis is a disease caused by autoantigen-responsive immune cells that disrupt the myelin in the central nervous system (CNS). Although immunosuppressive drugs are used to suppress symptoms, no definitive therapy exists. As in the experimental autoimmune encephalitis (EAE) model of multiple sclerosis, a partial sequence of the myelin oligodendrocyte glycoprotein (MOG35-55) was identified as a causative autoantigen. This suggests that the induction of immune tolerance that is specific to MOG35-55 would be a fundamental treatment for EAE. We previously reported that lipid nanoparticles (LNPs) containing an anionic phospholipid, phosphatidylserine (PS), in their lipid composition, can be used to deliver mRNA and that this leads to proteins of interest to be expressed in the spleen. In addition to the targeting capability of PS, PS molecules avoid activating the immune system. Physiologically, the recognition of PS on apoptotic cells suppresses immune activation against these cells by releasing cytokines, such as interleukin-10 (IL-10) and transforming growth factor (TGF)-β that negatively regulate immunity. In this study, we tested whether mRNA delivery of autoantigens to the spleen by PS-LNPs causes the expression of MOG35-55 antigens with minimal immune stimulation and whether this could be used to treat an EAE model by inducing immune tolerance.

Recent advances in mRNA cancer vaccines: meeting challenges and embracing opportunities

Since the successful application of messenger RNA (mRNA) vaccines in preventing COVID-19, researchers have been striving to develop mRNA vaccines for clinical use, including those exploited for anti-tumor therapy. mRNA cancer vaccines have emerged as a promising novel approach to cancer immunotherapy, offering high specificity, better efficacy, and fewer side effects compared to traditional treatments. Multiple therapeutic mRNA cancer vaccines are being evaluated in preclinical and clinical trials, with promising early-phase results. However, the development of these vaccines faces various challenges, such as tumor heterogeneity, an immunosuppressive tumor microenvironment, and practical obstacles like vaccine administration methods and evaluation systems for clinical application. To address these challenges, we highlight recent advances from preclinical studies and clinical trials that provide insight into identifying obstacles associated with mRNA cancer vaccines and discuss potential strategies to overcome them. In the future, it is crucial to approach the development of mRNA cancer vaccines with caution and diligence while promoting innovation to overcome existing barriers. A delicate balance between opportunities and challenges will help guide the progress of this promising field towards its full potential.

Lipid nanoparticles (LNPs) for in vivo RNA delivery and their breakthrough technology for future applications

RNA therapeutics show a significant breakthrough for the treatment of otherwise incurable diseases and genetic disorders by regulating disease-related gene expression. The successful development of COVID-19 mRNA vaccines further emphasizes the potential of RNA therapeutics in the prevention of infectious diseases as well as in the treatment of chronic diseases. However, the efficient delivery of RNA into cells remains a challenge, and nanoparticle delivery systems such as lipid nanoparticles (LNPs) are necessary to fully realize the potential of RNA therapeutics. While LNPs provide a highly efficient platform for the in vivo delivery of RNA by overcoming various biological barriers, several challenges remain to be resolved for further development and regulatory approval. These include a lack of targeted delivery to extrahepatic organs and a gradual loss of therapeutic potency with repeated doses. In this review, we highlight the fundamental aspects of LNPs and their uses in the development of novel RNA therapeutics. Recent advances in LNP-based therapeutics and preclinical/clinical studies are overviewed. Lastly, we discuss the current limitations of LNPs and introduce breakthrough technologies that might overcome these challenges in future applications.

Evaluation of a DoE based approach for comprehensive modelling of the effect of lipid nanoparticle composition on nucleic acid delivery

Therapeutic nucleic acids (TNAs) comprise an alternative to conventional drugs for cancer therapy. Recently, stable nucleic acid lipid particles (SNALPs) have been explored to deliver TNA efficiently and safely both in vitro and in vivo. Small interfering RNA (siRNA) and messenger RNA (mRNA) based drugs have been suggested for a wide range of pathologies, and their respective lipid nanoparticle (LNP) formulations have been optimised using a Design of Experiments (DoE) approach. However, it is uncertain as to whether data obtained from DoE using simple experimental outputs can be used to generate a general heuristic for delivery of diverse TNA both in vitro and in vivo. Using plasmid DNA (pDNA), for which limited DoE optimisation has been performed, and siRNA to represent the two extremities of the TNA spectrum in terms of size and biological requirements, we performed a comparative DoE for both molecules and assessed the predictive qualities of the model both in vitro and in vivo. By producing a minimum run of 24 SNALP formulations with different lipid compositions incorporating either pDNA or siRNA, DoE models were successfully established for predicting the effect of individual lipid composition on particle size, TNA encapsulation and transfection both in vitro and in vivo. The results showed that the particle size, and in vitro and in vivo transfection efficiency of both pDNA and siRNA SNALP formulations were affected by lipid compositions. The encapsulation efficiency of pDNA SNALPs but not siRNA SNALPs was affected by the lipid composition. Notably, the optimal lipid compositions of SNALPs for pDNA/siRNA delivery were not identical. Furthermore, in vitro transfection efficiency could not be used to predict promising LNP candidates in vivo. The DoE approach described in this study may provide a method for comprehensive optimisation of LNPs for various applications. The model and optimal formulation described in this study can serve as a foundation from which to develop other novel NA containing LNPs for multiple applications such as NA based vaccines, cancer immunotherapies and other TNA therapies.

Lipid-based nanoparticles as drug delivery systems for cancer immunotherapy

Immune checkpoint inhibitors (ICIs) have shown remarkable success in cancer treatment. However, in cancer patients without sufficient antitumor immunity, numerous data indicate that blocking the negative signals elicited by immune checkpoints is ineffective. Drugs that stimulate immune activation-related pathways are emerging as another route for improving immunotherapy. In addition, the development of nanotechnology presents a promising platform for tissue and cell type-specific delivery and improved uptake of immunomodulatory agents, ultimately leading to enhanced cancer immunotherapy and reduced side effects. In this review, we summarize and discuss the latest developments in nanoparticles (NPs) for cancer immuno-oncology therapy with a focus on lipid-based NPs (lipid-NPs), including the characteristics and advantages of various types. Using the agonists targeting stimulation of the interferon genes (STING) transmembrane protein as an exemplar, we review the potential of various lipid-NPs to augment STING agonist therapy. Furthermore, we present recent findings and underlying mechanisms on how STING pathway activation fosters antitumor immunity and regulates the tumor microenvironment and provide a summary of the distinct STING agonists in preclinical studies and clinical trials. Ultimately, we conduct a critical assessment of the obstacles and future directions in the utilization of lipid-NPs to enhance cancer immunotherapy.

mRNA: A promising platform for cancer immunotherapy

Messenger RNA (mRNA) is now in the limelight as a powerful tool for treating various human diseases, especially malignant tumors, thanks to the remarkable clinical outcomes of mRNA vaccines using lipid nanoparticle technology during the COVID-19 pandemic. Recent promising preclinical and clinical results that epitomize the advancement in mRNA and nanoformulation-based delivery technologies have highlighted the tremendous potential of mRNA in cancer immunotherapy. mRNAs can be harnessed for cancer immunotherapy in forms of various therapeutic modalities, including cancer vaccines, adoptive T-cell therapies, therapeutic antibodies, and immunomodulatory proteins. This review provides a comprehensive overview of the current state and prospects of mRNA-based therapeutics, including numerous delivery and therapeutic strategies.

From Bench to Bedside: Implications of Lipid Nanoparticle Carrier Reactogenicity for Advancing Nucleic Acid Therapeutics

In biomedical applications, nanomaterial-based delivery vehicles, such as lipid nanoparticles, have emerged as promising instruments for improving the solubility, stability, and encapsulation of various payloads. This article provides a formal review focusing on the reactogenicity of empty lipid nanoparticles used as delivery vehicles, specifically emphasizing their application in mRNA-based therapies. Reactogenicity refers to the adverse immune responses triggered by xenobiotics, including administered lipid nanoparticles, which can lead to undesirable therapeutic outcomes. The key components of lipid nanoparticles, which include ionizable lipids and PEG-lipids, have been identified as significant contributors to their reactogenicity. Therefore, understanding the relationship between lipid nanoparticles, their structural constituents, cytokine production, and resultant reactogenic outcomes is essential to ensure the safe and effective application of lipid nanoparticles in mRNA-based therapies. Although efforts have been made to minimize these adverse reactions, further research and standardization are imperative. By closely monitoring cytokine profiles and assessing reactogenic manifestations through preclinical and clinical studies, researchers can gain valuable insights into the reactogenic effects of lipid nanoparticles and develop strategies to mitigate undesirable reactions. This comprehensive review underscores the importance of investigating lipid nanoparticle reactogenicity and its implications for the development of mRNA-lipid nanoparticle therapeutics in various applications beyond vaccine development.

Nanotechnology boosts the efficiency of tumor diagnosis and therapy

The incidence and mortality of cancer are gradually increasing. The highly invasive and metastasis of tumor cells increase the difficulty of diagnosis and treatment, so people pay more and more attention to the diagnosis and treatment of cancer. Conventional treatment methods, including surgery, radiotherapy and chemotherapy, are difficult to eliminate tumor cells completely. And the emergence of nanotechnology has boosted the efficiency of tumor diagnosis and therapy. Herein, the research progress of nanotechnology used for tumor diagnosis and treatment is reviewed, and the emerging detection technology and the application of nanodrugs in clinic are summarized and prospected. The first part refers to the application of different nanomaterials for imaging in vivo and detection in vitro, which includes magnetic resonance imaging, fluorescence imaging, photoacoustic imaging and biomarker detection. The distinctive physical and chemical advantages of nanomaterials can improve the detection sensitivity and accuracy to achieve tumor detection in early stage. The second part is about the nanodrug used in clinic for tumor treatment. Nanomaterials have been widely used as drug carriers, including the albumin paclitaxel, liposome drugs, mRNA-LNP, protein nanocages, micelles, membrane nanocomplexes, microspheres et al., which could improve the drug accumulate in tumor tissue through enhanced permeability and retention effect to kill tumor cells with high efficiency. But there are still some challenges to revolutionize traditional tumor diagnosis and anti-drug resistance based on nanotechnology.

PepFect14 mediates the delivery of mRNA into human primary keratinocytes and in vivo

mRNA-based vaccines and candidate therapeutics have great potential in various medical fields. For the delivery of mRNA into target cells and tissues, lipid formulations are often employed. However, this approach could cause the activation of immune responses, making it unsuitable for the treatment of inflammatory conditions. Therefore, alternative delivery systems are highly demanded. In this study, we evaluated the transport efficiency and characteristics of cell-penetrating peptide PepFect14 (PF14) and mRNA nanoparticles in the presence of different additives. Our results show that all PF14-mRNA formulations entered cultured cells, while calcium chloride enhanced the transport and production of the encoded protein in HeLa and HaCaT cell lines, and polysorbate 80 did so in primary human keratinocytes. All formulations had similar physical properties and did not remarkably affect cell viability. By selectively blocking endocytosis pathways, we show that PF14-mRNA nanoparticles primarily entered HeLa cells via macropinocytosis and HaCaT cells via both macropinocytosis and clathrin-mediated endocytosis, while none of the blockers significantly affected the delivery into primary keratinocytes. Finally, subcutaneous injection of PF14-mRNA nanoparticles before inducing mouse irritant contact dermatitis resulted in the expression of a reporter protein without provoking harmful immune responses in the skin. Together, our findings suggest that PF14-mRNA nanoparticles have the potential for developing mRNA-based therapeutics for treating inflammatory skin conditions.

Lighting Up the Fire in the Microenvironment of Cold Tumors: A Major Challenge to Improve Cancer Immunotherapy

Immunotherapy includes immune checkpoint inhibitors (ICI) such as antibodies targeting cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) or the programmed cell death protein/programmed death ligand 1 (PD-1/PD-L1) axis. Experimental and clinical evidence show that immunotherapy based on immune checkpoint inhibitors (ICI) provides long-term survival benefits to cancer patients in whom other conventional therapies have failed. However, only a minority of patients show high clinical benefits via the use of ICI alone. One of the major factors limiting the clinical benefits to ICI can be attributed to the lack of immune cell infiltration within the tumor microenvironment. Such tumors are classified as "cold/warm" or an immune "desert"; those displaying significant infiltration are considered "hot" or inflamed. This review will provide a brief summary of different tumor properties contributing to the establishment of cold tumors and describe major strategies that could reprogram non-inflamed cold tumors into inflamed hot tumors. More particularly, we will describe how targeting hypoxia can induce metabolic reprogramming that results in improving and extending the benefit of ICI.

Stimulatory effect of fluoxetine and desipramine, but not mirtazapine on C26 colon carcinoma hepatic metastases formation: association with cytokines

Due to the high prevalence of depression among cancer patients, antidepressant medications are frequently administered as adjuvant treatment. However, the safety of such medications in the development of metastasis is unclear. In this study, we investigated the effects of fluoxetine, desipramine, and mirtazapine on the liver metastasis of murine C26 colon carcinoma (cc). Balb/c male mice were administered these antidepressants intraperitoneally (i.p.) for 14 days following intrasplenic injections of C26 colon carcinoma cells. Desipramine and fluoxetine, but not mirtazapine, significantly increased the number of tumor foci and total volume of the tumor in liver tissue. This effect was associated with a decrease in the ability of splenocytes to produce interleukin (IL)-1β and interferon (IFN)-γ and an increase in their ability to produce interleukin (IL)-10. Similar changes were observed in plasma IL-1β, IFN-γ, and IL-10 levels. The current study demonstrates that the stimulatory effect of desipramine and fluoxetine, but not mirtazapine, on experimental colon cancer liver metastasis is associated with a suppression of immune defenses against the tumor.

Immune-Modulating Lipid Nanomaterials for the Delivery of Biopharmaceuticals

In recent years, with the approval of preventative vaccines for pandemics, lipid nanoparticles have become a prominent RNA delivery vehicle. The lack of long-lasting effects of non-viral vectors is an advantage for infectious disease vaccines. With the introduction of microfluidic processes that facilitate the encapsulation of nucleic acid cargo, lipid nanoparticles are being studied as delivery vehicles for various RNA-based biopharmaceuticals. In particular, using microfluidic chip-based fabrication processes, nucleic acids such as RNA and proteins can be effectively incorporated into lipid nanoparticles and utilized as delivery vehicles for various biopharmaceuticals. Due to the successful development of mRNA therapies, lipid nanoparticles have emerged as a promising approach for the delivery of biopharmaceuticals. Biopharmaceuticals of various types (DNA, mRNA, short RNA, proteins) possess expression mechanisms that are suitable for manufacturing personalized cancer vaccines, while also requiring formulation with lipid nanoparticles. In this review, we describe the basic design of lipid nanoparticles, the types of biopharmaceuticals used as carriers, and the microfluidic processes involved. We then present research cases focusing on lipid-nanoparticle-based immune modulation and discuss the current status of commercially available lipid nanoparticles, as well as future prospects for the development of lipid nanoparticles for immune regulation purposes.

Lynch syndrome cancer vaccines: A roadmap for the development of precision immunoprevention strategies

Hereditary cancer syndromes (HCS) account for 5~10% of all cancer diagnosis. Lynch syndrome (LS) is one of the most common HCS, caused by germline mutations in the DNA mismatch repair (MMR) genes. Even with prospective cancer surveillance, LS is associated with up to 50% lifetime risk of colorectal, endometrial, and other cancers. While significant progress has been made in the timely identification of germline pathogenic variant carriers and monitoring and early detection of precancerous lesions, cancer-risk reduction strategies are still centered around endoscopic or surgical removal of neoplastic lesions and susceptible organs. Safe and effective cancer prevention strategies are critically needed to improve the life quality and longevity of LS and other HCS carriers. The era of precision oncology driven by recent technological advances in tumor molecular profiling and a better understanding of genetic risk factors has transformed cancer prevention approaches for at-risk individuals, including LS carriers. MMR deficiency leads to the accumulation of insertion and deletion mutations in microsatellites (MS), which are particularly prone to DNA polymerase slippage during DNA replication. Mutations in coding MS give rise to frameshift peptides (FSP) that are recognized by the immune system as neoantigens. Due to clonal evolution, LS tumors share a set of recurrent and predictable FSP neoantigens in the same and in different LS patients. Cancer vaccines composed of commonly recurring FSP neoantigens selected through prediction algorithms have been clinically evaluated in LS carriers and proven safe and immunogenic. Preclinically analogous FSP vaccines have been shown to elicit FSP-directed immune responses and exert tumor-preventive efficacy in murine models of LS. While the immunopreventive efficacy of "off-the-shelf" vaccines consisting of commonly recurring FSP antigens is currently investigated in LS clinical trials, the feasibility and utility of personalized FSP vaccines with individual HLA-restricted epitopes are being explored for more precise targeting. Here, we discuss recent advances in precision cancer immunoprevention approaches, emerging enabling technologies, research gaps, and implementation barriers toward clinical translation of risk-tailored prevention strategies for LS carriers. We will also discuss the feasibility and practicality of next-generation cancer vaccines that are based on personalized immunogenic epitopes for precision cancer immunoprevention.

Lipid-mRNA nanoparticles landscape for cancer therapy

Intracellular delivery of message RNA (mRNA) technique has ushered in a hopeful era with the successive authorization of two mRNA vaccines for the Coronavirus disease-19 (COVID-19) pandemic. A wide range of clinical studies are proceeding and will be initiated in the foreseeable future to treat and prevent cancers. However, efficient and non-toxic delivery of therapeutic mRNAs maintains the key limited step for their widespread applications in human beings. mRNA delivery systems are in urgent demand to resolve this difficulty. Recently lipid nanoparticles (LNPs) vehicles have prospered as powerful mRNA delivery tools, enabling their potential applications in malignant tumors via cancer immunotherapy and CRISPR/Cas9-based gene editing technique. This review discusses formulation components of mRNA-LNPs, summarizes the latest findings of mRNA cancer therapy, highlights challenges, and offers directions for more effective nanotherapeutics for cancer patients.

Liposome Formulation for Tumor-Targeted Drug Delivery Using Radiation Therapy

Targeted delivery of drugs or other therapeutic agents through internal or external triggers has been used to control and accelerate the release from liposomal carriers in a number of studies, but relatively few utilize energy of therapeutic X-rays as a trigger. We have synthesized liposomes that are triggered by ionizing radiation (RTLs) to release their therapeutic payload. These liposomes are composed of natural egg phosphatidylethanolamine (PE), 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), cholesterol, and 1,2-disteroyl-sn-glycero-3-phosphoethanolamine-N-[methoxy (polyethylene glycol)-2000] (DSPE-PEG-2000), and the mean size of the RTL was in the range of 114 to 133 nm, as measured by nanoparticle tracking analysis (NTA). The trigger mechanism is the organic halogen, chloral hydrate, which is known to generate free protons upon exposure to ionizing radiation. Once protons are liberated, a drop in internal pH of the liposome promotes destabilization of the lipid bilayer and escape of the liposomal contents. In proof of principle studies, we assessed RTL radiation-release of fluorescent tracers upon exposure to a low pH extracellular environment or exposure to X-ray irradiation. Biodistribution imaging before and after irradiation demonstrated a preferential uptake and release of the liposomes and their cargo at the site of local tumor irradiation. Finally, a potent metabolite of the commonly used chemotherapy irinotecan, SN-38, was loaded into RTL along with near infrared (NIR) fluorescent dyes for imaging studies and measuring tumor cell cytotoxicity alone or combined with radiation exposure, in vitro and in vivo. Fully loaded RTLs were found to increase tumor cell killing with radiation in vitro and enhance tumor growth delay in vivo after three IV injections combined with three, 5 Gy local tumor radiation exposures compared to either treatment modality alone.