Dendritic cell-targeted delivery of antigens using extracellular vesicles for anti-cancer immunotherapy.

Neoantigen delivery using extracellular vesicles (EVs) has gained extensive interest in recent years. EVs derived from tumour cells or immune cells have been used to deliver tumour antigens or antitumor stimulation signals. However, potential DNA contamination from the host cell and the cost of large-scale EV production hinder their therapeutic applications in clinical settings. Here, we develop an antigen delivery platform for cancer vaccines from red blood cell-derived EVs (RBCEVs) targeting splenic DEC-205+ dendritic cells (DCs) to boost the antitumor effect. By loading ovalbumin (OVA) protein onto RBCEVs and delivering the protein to DCs, we were able to stimulate and present antigenic OVA peptide onto major histocompatibility complex (MHC) class I, subsequently priming activated antigen-reactive T cells. Importantly, targeted delivery of OVA using RBCEVs engineered with anti-DEC-205 antibody robustly enhanced antigen presentation of DCs and T cell activation. This platform is potentially useful for producing personalised cancer vaccines in clinical settings.

αvß1 integrin is enriched in extracellular vesicles of metastatic breast cancer cells: A mechanism mediated by galectin-3.

Breast cancer cells release a large quantity of biocargo-bearing extracellular vesicles (EVs), which mediate intercellular communication within the tumour microenvironment and promote metastasis. To identify EV-bound proteins related to metastasis, we used mass spectrometry to profile EVs from highly and poorly metastatic breast cancer lines of human and mouse origins. Comparative mass spectrometry indicated that integrins, including αv and ß1 subunits, are preferentially enriched in EVs of highly metastatic origin over those of poorly metastatic origin. These results are consistent with our histopathological findings, which show that integrin αv is associated with disease progression in breast cancer patients. Integrin αv colocalizes with the multivesicular-body marker CD63 at a higher frequency in the tumour and is enriched in circulating EVs of breast cancer patients at late stages when compared with circulating EVs from early-stage patients. With a magnetic bead-based flow cytometry assay, we confirmed that integrins αv and ß1 are enriched in the CD63+ subsets of EVs from both human and mouse highly metastatic cells. By analysing the level of integrin αv on circulating EVs, this assay could predict the metastatic potential of a xenografted mouse model. To explore the export mechanism of integrins into EVs, we performed immunoprecipitation mass spectrometry and identified members of the galectin family as potential shuttlers of integrin αvß1 into EVs. In particular, knockdown of galectin-3, but not galectin-1, causes a reduction in the levels of cell surface integrins ß1 and αv, and decreases the colocalization of these integrins with CD63. Importantly, knockdown of galectin-3 leads to a decrease of integrin αvß1 export into the EVs concomitant with a decrease in the metastatic potential of breast cancer cells. Moreover, inhibition of the integrin αvß1 complex leads to a reduction in the binding of EVs to fibronectin, suggesting that integrin αvß1 is important for EV retention in the extracellular matrix. EVs retained in the extracellular matrix are taken up by fibroblasts, which differentiate into cancer associated fibroblasts. In summary, our data indicate an important link between EV-bound integrin αvß1 with breast cancer metastasis and provide additional insights into the export of integrin αvß1 into EVs in the context of metastasis.

[Expression of PTTG1 in gastric adenocarcinoma tissues and its relationship with prognosis].

Objective: To identify new prognostic markers and therapeutic targets for gastric adenocarcinoma. Methods: The public datasets of gastric adenocarcinoma collected from GEO database (GSE33335 and GSE63089) were downloaded for analysis. There were 70 GC tissues and paired normal tissues in the two profile datasets. Differentially expressed genes (DEGs) between GC tissues and normal stomach tissues were selected by the R software. Protein-protein interaction (PPI) of these DEGs were visualized by the Search Tool for the Retrieval of Interacting Genes (STRING). The key gene sets were analyzed by Cytoscape and Molecular Complex Detection (MCODE). The mRNA and protein expression levels of prognosis related genes identified by public database were confirmed by using GC tissues and paired normal tissues collected from July 2019 to September 2019 in Affiliated Hospital of Nantong University. Results: DEGs were identified in the two datasets by using R software. A total of 128 DEGs were detected, including 85 up-regulated genes (log(2)FC>1.2 and FDR<0.01) and 43 down-regulated genes (log(2)FC<-1.2 and FDR<0.01) in the GC tissues. PPI network model and MCODE model were established by using the Online String tool and Cytoscape software, and 27 key genes were obtained, including 25 genes related with prognosis of GC patients (P<0.05). We identified 14 significant DEGs in GC tissues, including cyclin B1 (CCNB1), polo-like kinase 1 (PLK1) and pituitary-tumor transforming gene (PTTG1), which were significantly enriched in the cell cycle pathway through KEGG pathway enrichment analysis. The positive expression rate of PTTG1 in GC tissues was 68.8% (22/32), significantly higher than 18.8% (6/32) in normal gastric tissues (P<0.05). Conclusions: The expression of PTTG1 is different in GC and gastric tissues, implicates it is the key gene in gastric carcinogenesis. The prognoses of GC patients with higher PTTG1 expression are worse. PTTG1 might participate in the development of gastric adenocarcinoma by regulating cell cycle.

Rural-urban differences in preferences for influenza vaccination among women of childbearing age: implications for local vaccination service implementation in Vietnam.

OBJECTIVES: Pregnant women and new mothers are among the most vulnerable to seasonal influenza; however, little is known about their preferences for flu vaccination. We examined the rural-urban differences in uptake, demand and willingness to pay (WTP) for influenza vaccination among women of childbearing age, to assess the feasibility of implementing locally produced vaccines in Vietnam. METHODS: A cross-sectional study was performed in both urban and rural areas of Hanoi in 2018. Socio-demographic characteristics, history of vaccination, demand and WTP for influenza vaccines were obtained. A multivariate logistic regression model was employed to identify the associated factors. RESULTS: Of 750 participants, 29.9% had had flu shots in the current or previous flu season and 64.3% indicated demand for this vaccine. The median of the maximum amount of WTP for influenza vaccination services was US$ 8.5 (IQR: 8.5-17.0). Women living in rural areas had a significantly lower uptake and higher demand, and were willing to pay less than women in urban locations (21.1% vs. 36.6%; 69% vs. 60.2%; and US $8.5 vs. US $11.7, respectively). For urban participants, factors associated with higher demand and WTP for flu shots included having ANC in health facilities and having been vaccinated against influenza in the past; for rural women, these factors were having suffered from influenza and hearing about it. CONCLUSIONS: This study informs the feasibility of implementing locally produced influenza vaccines in Vietnam. Educational programs, along with counselling services and government subsidies, should be implemented to improve the coverage, demand and WTP for the vaccine.

OBJECTIFS: Les femmes enceintes et les nouvelles mères sont parmi les plus vulnérables à la grippe saisonnière; cependant, on en sait peu sur leurs préférences pour la vaccination contre la grippe. Nous avons examiné les différences entre les zones rurales et urbaines dans l'adoption, la demande et la volonté de payer pour la vaccination antigrippale chez les femmes en âge de procréer, afin d'évaluer la faisabilité de la mise en œuvre de vaccins produits localement au Vietnam. MÉTHODES: Une étude transversale a été réalisée dans les zones urbaines et rurales de Hanoi en 2018. Les caractéristiques sociodémographiques, les antécédents de vaccination, la demande et la volonté de payer pour les vaccins antigrippaux ont été obtenus. Un modèle de régression logistique multivariée a été utilisé pour identifier les facteurs associés. RÉSULTATS: Sur 750 participantes, 29,9% s'étaient fait vacciner contre la grippe au cours de la saison grippale actuelle ou précédente, 64,3% ont indiqué une demande pour ce vaccin. La médiane du montant maximal de la volonté de payer pour les services de vaccination contre la grippe était de 8,5 USD (IQR: 8,5 à 17,0). Les femmes vivant dans les zones rurales avaient une adoption nettement plus faible, une demande plus élevée et étaient prêtes à payer moins que les femmes des zones urbaines (21,1% contre 36,6%; 69% contre 60,2%; et 8,5 USD contre 11,7 USD, respectivement). Pour les participantes urbaines, les facteurs associés à une demande plus élevée et à la volonté de payer pour les vaccins contre la grippe comprenaient le fait d'avoir des soins prénatals dans les établissements de santé et d'avoir été vaccinés contre la grippe dans le passé; pour les femmes rurales, ces facteurs comprenaient, avoir souffert de la grippe et en avoir entendu parler. CONCLUSIONS: Cette étude informe sur la faisabilité de la mise en œuvre de vaccins antigrippaux produits localement au Vietnam. Des programmes éducatifs, ainsi que des services de conseil et des subventions gouvernementales devraient être mis en œuvre pour améliorer la couverture, la demande et la volonté de payer pour le vaccin.

Extracellular Vesicles as an Efficient and Versatile System for Drug Delivery.

Despite the recent advances in drug development, the majority of novel therapeutics have not been successfully translated into clinical applications. One of the major factors hindering their clinical translation is the lack of a safe, non-immunogenic delivery system with high target specificity upon systemic administration. In this respect, extracellular vesicles (EVs), as natural carriers of bioactive cargo, have emerged as a promising solution and can be further modified to improve their therapeutic efficacy. In this review, we provide an overview of the biogenesis pathways, biochemical features, and isolation methods of EVs with an emphasis on their many intrinsic properties that make them desirable as drug carriers. We then describe in detail the current advances in EV therapeutics, focusing on how EVs can be engineered to achieve improved target specificity, better circulation kinetics, and efficient encapsulation of therapeutic payloads. We also identify the challenges and obstacles ahead for clinical translation and provide an outlook on the future perspective of EV-based therapeutics.

Complete genome sequence of a novel lytic phage infecting Aeromonas hydrophila, an infectious agent in striped catfish (Pangasianodon hypophthalmus).

The bacteriophage vB_AhM_PVN02 (PVN02), infecting Aeromonas hydrophila, was isolated from a striped catfish pond water sample in Can Tho City, Vietnam. The phage had high lytic activity with a latent period and burst size of approximately 20 min and 105 plaque-forming units per cell, respectively. Observation of the phage by transmission electron microscopy indicated that PVN02 belongs to the family Myoviridae. The genome of PVN02 is a double-stranded linear DNA with a length in 51,668 bp and a content of 52% GC. Among the 64 genes, 16 were predicted to encode proteins with predicted functions. No virulence or antibiotic resistance genes were found in the genome, suggesting it would be a useful biocontrol agent. Classification of the phage based on sequence comparisons, phylogenetic analysis, and gene-sharing networks was carried out, and it was found to be the first representative of a new species within a previously undefined genus in the family Myoviridae. This study confirmed that PVN02 is a novel lytic phage that could potentially be used as an agent to control Aeromonas hydrophila in striped catfish in the Mekong Delta, Vietnam.