Exosomes: an overview of biogenesis, composition and role in ovarian cancer

Abstract

Exosomes are tiny membrane-bound vesicles that are over produced by most proliferating cell types during normal and pathological states. Their levels are up-regulated during pregnancy and disease states such as cancer. Exosomes contain a wide variety of proteins, lipids, RNAs, non-transcribed RNAs, microRNAs and small RNAs that are representative to their cellular origin and shuttle from a donor cell to a recipient cell. From intercellular communication to tumor proliferation, exosomes carry out a diverse range of functions, both helpful and harmful. Useful as biomarkers, exosomes may be applicable in diagnostic assessments as well as cell-free anti-tumor vaccines. Exosomes of ovarian cancer contain different set of proteins and miRNAs compared to exosomes of normal, cancer-free individuals. These molecules may be used as multiple "barcode" for the development of a diagnostic tool for early detection of ovarian cancer.

Figure 1

Biogenesis and release of exosomes: diagram depicted the well-accepted model for exosome biogenesis and release.

Figure 2

Schematic of exosome secretion in a cancer cell model. Exosomes are secreted via a constitutive pathway involving the Trans-Golgi Network and/or inducible pathways, which can be activated by p53 and other stimuli such as Rab proteins. Reproduced from Henderson and Azorsa (19).