Exosomes Derived From Oral Squamous Cell Carcinoma: Isolation,Identification And Gene Expression Profile

Background: Oral squamous cell carcinoma(OSCC)is the most common malignancy of the oral and maxillofacial charactered with recurrence,metastasis and poor prognosis.It is very significant to improve the poor prognosis,the low survival rate and high recurrence rate of OSCC via detecting special biomarkers and developing a non-invasive diagnostic and screening tool.Recent years,with the lucubrating on exosomes,its roles in tumorigenesis,growth,metastasis and noninvasive diagnosis have been revealed,which make exosomes became a new direction for cancer research.Objective:This study aim to isolate and identify the exosomes derived from oral squamous cell carcinoma cells and human oral epithelial cells and examine the exosomal gene expression profile,which can provide the foundation for detecting special exosome related to oral squamous cell carcinoma.Methods: Exosomes were isolated from cell culture supernatant by ultracentrifugation and further examined with transmission electron microscopy(TEM),particle size analyzer,western blotting and flow cytometry.Using high-throughput sequencing technology to screen exosomal gene expression profiles for finding differently expressed genes,then creature information analysis were conducted to define gene functions and biological pathways.Results: 1)Exosomes were round or oval in shape with a diameter between 30 to 150 nm,and they were positive in the expressions of ALIX,CD63 and CD81 proteins.2)A total of 336 genes show differently expressed between Cal27 and HOEC-derived exosomes,in which 122 up-regulated and 214 down-regulated.3)KEGG analysis showed that differently expressed genes mainly enriched in 30 biological pathways including Wnt signaling pathway and PI3K-Akt signaling pathway.4)GO analysis showed that differentially expressed genes involved in various processes such as protein binding,nucleic acid binding and cell motility.5)32 differentially expressed genes(such as ACVR1 C,CDH20,THBS1,etc.)which are closely related to the development of cancer were screened from the differentially expressed genes by bioinformatics analysis and literature review.6)32 genes were mainly enriched in 11 biological pathways(for example,Wnt signaling pathway,PI3K-Akt signaling pathway,TGF-beta signaling pathway,etc.).Conclusion: 1)Abundant exosomes can be secreted by Oral squamous cell carcinoma and human oral epithelial cells.2)The gene expression profiles were obviously different between the two kinds of exosomes in which we screened 32 differentially expressed genes and 11 biological pathways that may be associated with the biogenesis and development of oral squamous cell carcinoma.