Isolation and Characterization of Exosomes Derived From Breast Cancer MDA-MB-231 Cell Line

Abstract

Background: Exosomes are membrane nanovesicles, 30 to 100 nm in diameter, secreted by most cell types. Besides playing many biological roles, especially in cell-cell communication, scientific proof indicated that the pathology of so many human cancers is closely related to many biologic elements in exosomes. They may serve as useful biomarkers for treatment, prognosis, and detection. Cancer cells produce more exosomes, inducing changes in target cells (near or distant from the tumor), such as metastasis and chemotherapy resistance. Therefore, isolation, identification, and analysis of these microvesicles seem essential. Objectives: The current study aimed at collecting and purifying microvesicles secreted from breast cancer cells and confirming the identity of the obtained exosomes using methods assessing size and morphology. Methods: In recent research, the MDA-MB-231 cell line was grown under standard conditions. Released exosomes were collected and ultra-centrifuged. Scanning (SEM) and transmission (TEM) electron microscopes, atomic force microscopy (AFM), and dynamic light scattering (DLS) were used to assess exosome size. Results: The obtained data revealed that MDA-MB-231 cells produced exosomes. The nanovesicles were isolated from the culture medium of MDA-MB-231 cells by applying different strategies, including differential centrifugation, filtration, and ultracentrifugation. The exosomes were characterized; they had a size of 30 - 100 nm and spherical shape. Conclusions: Intercellular communication can be mediated through direct cell-cell contact or transfer of secreted molecules. In the last two decades, a third mechanism for intercellular communication has emerged that involves intercellular transfer of extracellular vesicles (exosomes). Due to their many functions in the body, it is of great importance to purely isolate and recognize exosomes to understand their modes of action as the first step in the advancement of researches. However, more research is required to obtain cost-effective and efficient methods. It was found that MDA-MB-231 cells release exosomes. They are spherical and 30-100 nm in diameter. The use of a combination strategy for the first time was useful in isolating exosomes derived from MDA-MB-231 cells without disturbing their structure. Further studies are required to compile a uniform protocol for exosome isolation in medical research.