Search Results (89)

Background/Objectives: Trophoblast cell surface antigen 2 (Trop2), a transmembrane glycoprotein overexpressed in a broad spectrum of epithelial malignancies but minimally expressed in normal tissues, has emerged as a clinically relevant prognostic biomarker and therapeutic target, particularly in breast cancer. This study aims to develop an enhanced way of targeting Trop2 expression in tumors and blocking it using extracellular vesicles (EVs) bioengineered to express a nanobody sequence against Trop2 (NB60 E). Methods: Here, a plasmid construct was designed to express the Trop2 sequence, NB60, flanked with HA tag and myc epitope and a PDGFR transmembrane domain in the C-terminal region, and was transfected into HEK293T cells for EVs isolation. The potency of NB60 E to knock down Trop2 in letrozole-resistant breast cancer cells (LTLT-Ca and MDA-MB-468 cells) was initially investigated. Thereafter, the effects of NB60 E on the cell viability and downstream signaling pathway of Trop2 via MTT assay and Western blotting were determined. Lastly, we also examined whether NB60 E treatment in Jurkat T cells affects IL-6, TNF-α, and IL-2 cytokine production by enzyme-linked immunosorbent assay (ELISA). Results: Results revealed treatment with NB60 E significantly reduced surface Trop2 expression across both cell lines by 23.5 ± 1.5% in MDA-MB-468, and 61.5 ± 1.5% in LTLT-Ca, relative to the HEK293T-derived control EVs (HEK293T E). NB60 E treatment resulted in a marked reduction in LTLT-Ca cell viability by 52.8 ± 0.9% at 48 h post-treatment. This was accompanied by downregulation of key oncogenic signaling molecules: phosphorylated ERK1/2 (p-ERK 1/2) decreased by 30 ± 4%, cyclin D1 by 67 ± 11%, phosphorylated STAT3 (p-STAT3) by 71.8 ± 1.6%, and vimentin by 40.8 ± 1.4%. ELISA analysis revealed significant decreases in IL-6 (−57.5 ± 1.5%, 7.4 ± 0.35 pg/mL) and TNF-α (−32.1 ± 0.3%, 6.1 ± 1.2 pg/mL) levels, coordinated by an increase in IL-2 secretion (22.1 ± 2.7%, 49.2 ± 1.1 pg/mL). Quantitative analysis showed marked reductions in the number of nodes (−45 ± 4.4%), junctions (−55 ± 3.5%), and branch points (−38 ± 1.2%), indicating suppression of angiogenic capacity. In vivo experiment using near-infrared Cy7 imaging demonstrated rapid and tumor-selective accumulation of NB60 E within 4 h post-administration, followed by efficient systemic clearance by 24 h. The in vivo results demonstrate the effectiveness of NB60 E in targeting Trop2-enriched tumors while being efficiently cleared from the system, thus minimizing off-target interactions with normal cells. Lastly, Trop2 expression in LTLT-Ca tumor xenografts revealed a significant reduction of 41.0 ± 4% following NB60 E treatment, confirming efficient targeted delivery. Conclusions: We present a first-in-field NB60 E-grafted EV therapy that precisely homes to Trop2-enriched breast cancers, silences multiple growth-and-invasion pathways, blocks angiogenesis, and rewires cytokine crosstalk, achieving potent antitumor effects with self-clearing, biomimetic carriers. Our results here show promising potential for the use of NB60 E as anti-cancer agents, not only for letrozole-resistant breast cancer but also for other Trop2-expressing cancers. Full article

Background/Objectives: In response to the COVID-19 pandemic, we developed a vaccine candidate against SARS-CoV-2. Spike Ferritin Nanoparticle (SpFN) comprises 24 identical prefusion-stabilized spike proteins anchored to a self-assembled nanoparticle. Organized along the three-fold axis of the ferritin particle, eight SARS-CoV-2 spike trimers are presented per nanoparticle. Methods: Here, we describe the CGMP processes for manufacturing SpFN using transient transfection of Expi293F cells. Results: The final yield of SpFN was ~10 mg per liter of media supernatant. The resulting protein is stable in cold storage for two years at −20 °C, as well as for a month at room temperature, and can withstand multiple freeze/thaw cycles. SpFN material produced using the CGMP protocols adjuvanted with Army Liposomal Formulation-QS-21 (ALFQ) elicited potent neutralizing antibodies against WA-1, Alpha, Beta, and Delta variants in mice as measured by a pseudovirus neutralization assay. Conclusions: This work demonstrates rapid development and scaled-up production of clinical-grade SARS-CoV-2 vaccine protein material, allowing permissive storage and transport conditions, and serves as a framework for recombinant protein production for future emergent pathogens. Full article

Antigenicity and immunogenicity define a potent immunogen in vaccinology. Nowadays, there are simplified platforms to produce nanocarriers for small-peptide antigen delivery, derived from various infectious agents for the treatment of a variety of diseases, based on virus-like particles (VLPs). They have good cell-penetrating properties and protective action for target molecules from degradation. Human papillomavirus (HPV) causes anogenital warts and six types of cancer in infected women, men, or children, posing a challenge to global public health. The HPV capsid is composed of viral type-specific L1 and evolutionarily conserved L2 proteins. Produced in heterologous systems, the L1 protein can self-assemble into VLPs, nanoparticles sized around 50–60 nm, used as prophylactic vaccines. Devoid of the viral genome, they are safe for users, offering no risk of infection because VLPs do not replicate. The immune response induced by HPV VLPs is promoted by conformational viral epitopes, generating effective T- and B-cell responses. Produced in different cell systems, HPV16 L1 VLPs can be obtained on a large scale for use in mass immunization programs, which are well established nowadays. The expression of heterologous proteins was evaluated at various transfection times by transfecting cells with vectors encoding codon-optimized HPV16L1 and HPV16L2 genes. Immunological response induced by chimeric HPV16 L1/L2 VLP was evaluated through preclinical assays by antibody production, suggesting the potential of broad-spectrum protection against HPV as a prophylactic nanovaccine. These platforms can also offer promising therapeutic strategies, covering the various possibilities for complementary studies to develop potential preventive and therapeutic vaccines with broad-spectrum protection, using in silico new epitope selection and innovative nanotechnologies to obtain more effective immunobiologicals in combating HPV-associated cancers, influenza, hepatitis B and C, tuberculosis, human immunodeficiency virus (HIV), and many other illnesses. Full article

In recent years, combination chemotherapy with therapeutic nucleic acids has emerged as a promising strategy to enhance the effectiveness of cancer therapy. However, developing an effective co-delivery system to simultaneously transport both chemotherapeutic drugs and nucleic acids remains challenging. Herein, we fabricated cholesterol-conjugated polyion complex nanoparticles (PCNs) for combination delivery of hydrophobic paclitaxel (PTX) and hydrophilic miR-34a. Cholesterol was conjugated to polyethylenimine (PEI) and hyaluronic acid (HA), producing C–PEI and C–HA, respectively. PTX was initially encapsulated within the hydrophobic core formed by the self-assembly of C–HA and C–PEI, yielding polyion complex nanoparticles (PTX@C–HA/C–PEI PCNs). Subsequently, the negatively charged miR-34a was electrostatically complexed with the cationic C–PEI moieties to generate miR-34a/PTX@C–HA/C–PEI PCNs. These PCNs exhibited a nanoscale structure with a uniform size distribution and demonstrated low cytotoxicity in colon cancer cells. Fluorescence microscopy confirmed efficient cytosolic delivery of C–HA/C–PEI PCNs in colon carcinoma cells. Furthermore, combination delivery of PTX and miR-34a using C–HA/C–PEI PCNs exhibited significantly enhanced transfection efficiency and cellular uptake for human colon cancer cells. Notably, PTX/miR-34a@C–HA/C–PEI PCNs effectively downregulated critical oncogenic targets, including Notch1, Snail1, and BCL-2, resulting in reduced cancer cell migration and proliferation. These findings indicate that PTX/miR-34a@C–HA/C–PEI PCNs hold significant potential as an innovative combination delivery platform, offering improved therapeutic efficacy for colon cancer therapy. Full article

Background/Objectives: SARS-CoV-2 vaccine candidates comprising the receptor binding domain (RBD) of the spike protein have been shown to confer protection against infection. Previous research evaluating vaccine candidates with SARS-CoV-2 RBD fused to ferritin (RBD-ferritin) and other scaffolds suggested that multimeric assemblies of RBD can enhance antigen presentation to improve the potency and breadth of immune responses. Though RBDs directly fused to a self-assembling scaffold can be delivered as messenger RNA (mRNA) formulated with lipid nanoparticles (LNPs), reports of SARS-CoV-2 vaccine candidates that combine these approaches remain scarce. Methods: Here, we designed RBD fused to AP205 or TIP60 self-assembling nanoparticles following a search of available structures focused on several scaffold properties. RBD-AP205 and RBD-TIP60 were tested for antigenicity following transfection and for immunogenicity and neutralization potency when delivered as mRNA in mice, with RBD-ferritin as a direct comparator. Results: All scaffolded RBD constructs were readily secreted to transfection supernatant and showed antigenicity in ELISA, though clear heterogeneity in assembly was observed. RBD-AP205 and RBD-TIP60 also exhibited robust antibody binding and neutralization titers in mice that were comparable to those elicited by RBD-ferritin or a full-length membrane-bound spike. Conclusions: These data suggest that AP205 and TIP60 can present RBD as effectively as ferritin and induce similar immune responses. By describing additional scaffolds for multimeric display that accommodate mRNA delivery platforms, this work can provide new tools for future vaccine design efforts. Full article

Background: Lipid nanoparticles (LNPs) represent one of the most effective non-viral vectors for nucleic acid delivery and have demonstrated clinical success in siRNA therapies and mRNA vaccines. While considerable research has focused on optimizing ionizable lipids and helper lipids, the impact of PEGylated lipid content on LNP-mediated mRNA delivery, especially in terms of in vitro transfection efficiency and in vivo performance, remains insufficiently understood. Methods: In this study, LNPs were formulated using a self-synthesized ionizable lipid and varying molar ratios of DMG-PEG2000. Nanoparticles were prepared via nanoprecipitation, and their physicochemical properties, mRNA encapsulation efficiency, cellular uptake, and transfection efficiency were evaluated in HeLa and DC2.4 cells. In vivo delivery efficiency and organ distribution were assessed in mice following intravenous administration. Results: The PEGylated lipid content exerted a significant influence on both the in vitro and in vivo performance of LNPs. A bell-shaped relationship between PEG content and transfection efficiency was observed: 1.5% DMG-PEG2000 yielded optimal mRNA transfection in vitro, while 5% DMG-PEG2000 resulted in the highest transgene expression in vivo. This discrepancy in optimal PEG content may be attributed to the trade-off between cellular uptake and systemic circulation: lower PEG levels enhance cellular internalization, whereas higher PEG levels improve stability and in vivo bioavailability at the expense of cellular entry. Furthermore, varying the PEG-lipid content enabled the partial modulation of organ distribution, offering a formulation-based strategy to influence biodistribution without altering the ionizable lipid structure. Conclusions: This study highlights the critical role of PEGylated lipid content in balancing nanoparticle stability, cellular uptake, and in vivo delivery performance. Our findings provide valuable mechanistic insights and suggest a straightforward formulation-based strategy to optimize LNP/mRNA systems for therapeutic applications. Full article

Electroporation-mediated gene delivery is a cornerstone of synthetic biology, offering several advantages over other methods: higher efficiencies, broader applicability, and simpler sample preparation. Yet, electroporation protocols are often challenging to integrate into highly multiplexed workflows, owing to limitations in their scalability and tunability. These challenges ultimately increase the time and cost per transformation. As a result, rapidly screening genetic libraries, exploring combinatorial designs, or optimizing electroporation parameters requires extensive iterations, consuming large quantities of expensive custom-made DNA and cell lines or primary cells. To address these limitations, we have developed a High-Throughput Microfluidic Electroporation (HTME) platform that includes a 384-well electroporation plate (E-Plate) and control electronics capable of rapidly electroporating all wells in under a minute with individual control of each well. Fabricated using scalable and cost-effective printed-circuit-board (PCB) technology, the E-Plate significantly reduces consumable costs and reagent consumption by operating on nano to microliter volumes. Furthermore, individually addressable wells facilitate rapid exploration of large sets of experimental conditions to optimize electroporation for different cell types and plasmid concentrations/types. Use of the standard 384-well footprint makes the platform easily integrable into automated workflows, thereby enabling end-to-end automation. We demonstrate transformation of E. coli with pUC19 to validate the HTME’s core functionality, achieving at least a single colony forming unit in more than 99% of wells and confirming the platform’s ability to rapidly perform hundreds of electroporations with customizable conditions. This work highlights the HTME’s potential to significantly accelerate synthetic biology Design-Build-Test-Learn (DBTL) cycles by mitigating the transformation/transfection bottleneck. Full article

Background: Cancer stem cells (CSCs) are a subpopulation of cancer cells known for their self-renewal capacity, tumorigenicity, and resistance to treatment. Toll-like receptor 3 (TLR3) plays a complex role in cancer, exhibiting both pro-apoptotic and pro-tumorigenic effects. This study investigates the pro-tumorigenic role of TLR3, specifically its impact on CSCs in head and neck cancer. Methods: We have investigated Detroit 562, FaDu and SQ20B cell lines, the latter being stably transfected with a plasmid containing inducible shRNA for TLR3, by cultivating them to form tumor spheres in order to study CSCs. Results: Our findings demonstrate that TLR3 activation promotes stemness in head and neck cancer cell lines. This is evidenced by increased tumor sphere formation, promotion of epithelial-to-mesenchymal transition (EMT), upregulated stemness gene expression, and elevated aldehyde dehydrogenase (ALDH) activity. Conditional TLR3 knockdown abolished tumor sphere formation, confirming its important role. Furthermore, TLR3 activation triggers the secretion of damage-associated molecular patterns (DAMPs) into the tumor microenvironment, leading to increased cancer cell migration. This was inhibited by DAMP inhibitors. In patient tissue samples, we observed co-localization of TLR3 with stemness markers CD133 and ALDH1, as well as with heat shock protein 70 (HSP70) and receptor for advanced glycation end products (RAGE). We then explored potential CSC-targeted therapies, initially combining the apoptosis inducer poly (I:C) with DAMP inhibitors and γ-irradiation. While this combination proved effective in adherent cells, it failed to eliminate tumor spheres. Nevertheless, we discovered that proton radiotherapy, particularly when combined with aspirin (HMGB1 inhibitor) and poly (I:C), effectively eliminates CSCs. Conclusions: This novel combination holds promise for the development of new therapeutic strategies for head and neck cancers, particularly given the promising results of proton therapy in treating this disease. Full article

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a foodborne pathogen that causes a variety of diseases, ranging from self-limiting gastroenteritis to life-threatening extra-intestinal diseases such as hemolytic uremic syndrome. EspF, an effector protein secreted by the type III secretion system of EHEC, is primarily responsible for the development of inflammatory colitis. Our previous study revealed that EspF interacts with the host Annexin A6 (ANXA6) protein and targets the endoplasmic reticulum (ER). Given the critical effects of ER stress on the host responses of gastroenteritis, we explored the role of EspF–ANXA6 interaction in ER stress. Caco-2 cells were infected with different strains of EHEC and transfected with modified plasmids to establish in vitro research models. Our results revealed that infection with espF-deletion EHEC strains significantly exacerbated ER stress. Specifically, the phosphorylation of eIF2α was elevated, and the expression levels of BiP, ATF4, and CHOP were increased by more than 15% compared to those in cells infected with wild-type EHEC strains. Further experiments showed that EspF co-localizes with BiP and down-regulates the PERK pathway. Meanwhile, the EspF–ANXA6 interaction could aggravate the inhibition of the PERK pathway and stimulate calcium influx to disturb ER homeostasis, eventually leading to apoptosis. Our findings suggest that the EspF–ANXA6 interaction could inhibit ER stress through the PERK pathway, which may limit cell-to-cell communication and block the clearance of bacteria in host cells. Full article

Background/Objectives: Virus-like particles (VLPs) represent an attractive platform for delivering vaccine formulations, combining a high biosafety profile with a potent immune-stimulatory ability. VLPs are non-infectious, non-replicating, self-assembling nanostructures that can be exploited to efficiently expose membrane-tethered glycoproteins such as the SARS-CoV-2 Spike (S) protein, the main target of approved preventive vaccines. Here, we describe the development and preclinical validation of Simian Immunodeficiency Virus (SIV)-based GFP-labeled VLPs displaying S from the B.1.617.2 (Delta) variant (VLP/S-Delta) for inducing persistent anti-SARS-CoV-2 neutralizing antibodies (nAbs) and S-specific T cell responses in mice. Methods: SIV-derived VLP/S-Delta were produced by co-transfecting a plasmid expressing SIVGag-GFP, required for VLP assembly and quantification by flow virometry, a plasmid encoding the Delta S protein deleted in the cytoplasmic tail (CT), to improve membrane binding, and a VSV.G-expressing plasmid, to enhance VLP uptake. Recovered VLPs were titrated by flow virometry and characterized in vitro by transmission electron microscopy (TEM) and confocal microscopy (CLSM). BALB/c mice were immunized intramuscularly with VLP/S-Delta following a prime–boost regimen, and humoral and cellular immune responses were assessed. Results: VLP/S-Delta were efficiently pseudotyped with CT-truncated S-Delta. After BALB/c priming, VLP/S-Delta elicited both specific anti-RBD IgGs and anti-Delta nAbs that significantly increased after the boost and were maintained over time. The prime–boost vaccination induced similar levels of cross-nAbs against the ancestral Wuhan-Hu-1 strain as well as cross-nAbs against Omicron BA.1, BA.2 and BA.4/5 VoCs, albeit at lower levels. Moreover, immunization with VLP/S-Delta induced S-specific IFNγ-producing T cells. Conclusions: These data suggest that SIV-based VLPs are an appropriate delivery system for the elicitation of efficient and sustained humoral and cellular immunity in mice, paving the way for further improvements in the immunogen design to enhance the quality and breadth of immune responses against different viral glycoproteins. Full article

Spermatogonial stem cells (SSCs) possess the characteristics of self-renewal and differentiation, as well as the ability to generate functional sperm. Their unique stemness has broad applications in male infertility treatment and species preservation. In rodents, research on SSCs has been widely reported, but progress is slow in large livestock such as cattle and pigs due to long growth cycles, difficult proliferation in vitro, and significant species differences. Previously, we showed that histone 3 (H3) lysine 9 (K9) trimethylation (H3K9me3) is associated with the proliferation of bovine SSCs. Here, we isolated and purified SSCs from calf testicular tissues and investigated the impact of different H3K9me3 levels on the in vitro proliferation of bovine SSCs. The enriched SSCs eventually formed classical stem cell clones in vitro in our feeder-free culture system. These clones expressed glial cell-derived neurotrophic factor family receptor alpha-1 (GFRα1, specific marker for SSCs), NANOG (pluripotency protein), C-KIT (germ cell marker), and strong alkaline phosphatase (AKP) positivity. qRT-PCR analysis further showed that these clones expressed the pluripotency genes NANOG and SOX2, and the SSC-specific marker gene GFRα1. To investigate the dynamic relationship between H3K9me3 levels and SSC proliferation, H3K9me3 levels in bovine SSCs were first downregulated using the methyltransferase inhibitor, chaetocin, or transfection with the siRNA of H3K9 methyltransferase suppressor of variegation 3-9 homologue 1 (SUV39H1). The EDU (5-Ethynyl-2′-deoxyuridine) assay revealed that SSC proliferation was inhibited. Conversely, when H3K9me3 levels in bovine SSCs were upregulated by transfecting lysine demethylase 4D (KDM4D) siRNA, the EDU assay showed a promotion of cell proliferation. In summary, this study established a feeder-free culture system to obtain bovine SSCs and explored its effects on the proliferation of bovine SSCs by regulating H3K9me3 levels, laying the foundation for elucidating the regulatory mechanism underlying histone methylation modification in the proliferation of bovine SSCs. Full article

We propose a nucleic acids dilution-induced assembly (NADIA) method for the preparation of lipid nanoparticles. In the conventional method, water-soluble polymers such as nucleic acids and proteins are mixed in the aqueous phase. In contrast, the NADIA method, in which self-assembly is triggered upon dilution, requires dispersion in an alcohol phase without precipitation. We then investigated several alcohols and discovered that propylene glycol combined with sodium chloride enabled the dispersion of plasmid DNA and protamine sulfate in the alcohol phase. The streamlined characteristics of the NADIA method enable the preparation of extracellular vesicles-mimicking lipid nanoparticles (ELNPs). Among the mixing methods using a micropipette, a syringe pump, and a microfluidic device, the lattermost was the best for decreasing batch-to-batch differences in size, polydispersity index, and transfection efficiency in HepG2 cells. Although ELNPs possessed negative ζ-potentials and did not have surface antigens, their transfection efficiency was comparable to that of cationic lipoplexes. We observed that lipid raft-mediated endocytosis and macropinocytosis contributed to the transfection of ELNPs. Our strategy may overcome the hurdles linked to supply and quality owing to the low abundance and heterogeneity in cell-based extracellular vesicles production, making it a reliable and scalable method for the pharmaceutical manufacture of such complex formulations. Full article

We describe the current Good Manufacturing Practice (cGMP) production and subsequent characterization of eOD-GT8 60mer, a glycosylated self-assembling nanoparticle HIV-1 vaccine candidate and germline targeting priming immunogen. Production was carried out via transient expression in the human embryonic kidney 293 (HEK293) cell line followed by a combination of purification techniques. A large-scale cGMP (200 L) production run yielded 354 mg of the purified eOD-GT8 60mer drug product material, which was formulated at 1 mg/mL in 10% sucrose in phosphate-buffered saline (PBS) at pH 7.2. The clinical trial material was comprehensively characterized for purity, antigenicity, glycan composition, amino acid sequence, and aggregation and by several safety-related tests during cGMP lot release. A comparison of the purified products produced at the 1 L scale and 200 L cGMP scale demonstrated the consistency and robustness of the transient transfection upstream process and the downstream purification strategies. The cGMP clinical trial material was tested in a Phase 1 clinical trial (NCT03547245), is currently being stored at −80 °C, and is on a stability testing program as per regulatory guidelines. The methods described here illustrate the utility of transient transfection for cGMP production of complex products such as glycosylated self-assembling nanoparticles. Full article

SARS-CoV-2 virus, the causative agent of COVID-19, has produced the largest pandemic in the 21st century, becoming a very serious health problem worldwide. To prevent COVID-19 disease and infection, a large number of vaccines have been developed and approved in record time, including new vaccines based on mRNA encapsulated in lipid nanoparticles. While mRNA-based vaccines have proven to be safe and effective, they are more expensive to produce compared to conventional vaccines. A special type of mRNA vaccine is based on self-amplifying RNA (saRNA) derived from the genome of RNA viruses, mainly alphaviruses. These saRNAs encode a viral replicase in addition to the antigen, usually the SARS-CoV-2 spike protein. The replicase can amplify the saRNA in transfected cells, potentially reducing the amount of RNA needed for vaccination and promoting interferon I responses that can enhance adaptive immunity. Preclinical studies with saRNA-based COVID-19 vaccines in diverse animal models have demonstrated the induction of robust protective immune responses, similar to conventional mRNA but at lower doses. Initial clinical trials have confirmed the safety and immunogenicity of saRNA-based vaccines in individuals that had previously received authorized COVID-19 vaccines. These findings have led to the recent approval of two of these vaccines by the national drug agencies of India and Japan, underscoring the promising potential of this technology. Full article

Non-viral vectors have been developing in gene delivery due to their safety and low immunogenicity. But their transfection effect is usually very low, thus limiting the application. Hence, we designed eight peptides (compounds 1–8). We compared their performances; compound 8 had the best transfection efficacy and biocompatibility. The transfection effect was similar with that of PEI, a most-widely-employed commercial transfection reagent. Atomic force microscope (AFM) images showed that the compound could self-assemble and the self-assembled peptide might encapsulate DNA. Based on these results, we further analyzed the inhibitory result in cancer cells and found that compound 8 could partially fight against Hela cells. Therefore, the compound is promising to pave the way for the development of more effective and less toxic transfection vectors. Full article