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.