Morphological Characterization And Transcriptome Profiling Of Exosomes From Breast Cancer Cells

With the increasing incidence of cancer, it has been attracted our moreand more concerns. Just behind cardiovascular disease, cancer has becomethe second largest threat to human life and health. The clinicalinvestigations show that cancer is always diagnosed and treated at its latestage and thus leads to high mortality. Therefore, early diagnosis andclinical intervention are critical to overcome this disease.It is well established that most cancer patient die from metastasis bywhich tumor cells could be delivered to other sites and tissues in the bodythrough the bloodstream circulation (circulating tumor cells). However,recent studies indicate cancer cell-derived exosomes are also involved inmetastasis. These exosomes contain a variety of proteins and nucleic acids,and have been reported to be functionally involved in the growth of tumors,angiogenesis, metastasis and would be served as a new potential biomarkerin early diagnosis.This study focuses on the exosomes derived from breast cancer cells.Firstly, the exosomes from breast cancer cell MDA-MB-231were isolatedand purified by ultracentrifugation. Secondly, the morphology wascharacterized by low vacuum atomic force microscopy, dynamic lightscattering. The exosome specific protein Flotillin-1was analyzed byWestern Blot. Finally, I performed exosome transcripome analysis byRNA-seq. For the first time this study reported breast cancer exosometranscripome by deep sequencing. The result showed many genes in breastcancer exosomes are involved in cell adhesion, communication, cell cycleand metabolic process, particularly they are highly associated with integrin signalling pathway. This work provided the overall information of geneexpression in breast cancer exoxome and offered a solid base for furtherin-depth investigation of their roles in breast cancer metastasis.