Exploring the role of Rab3 in exosome release from prostate cancer cells

Abstract

Exosomes are extracellular vesicles (EVs) released by cells upon fusion of multivesicular bodies (MVBs) with the plasma membrane (PM). Various aspects concerning the molecular mechanisms involved in exosome biogenesis and release remain unclear and it is important to study this further to better understand the biology of these vesicles. It has been shown in many studies that exosomes contain proteins, lipids and genetic material that can be transferred to recipient cells. Exosomes have also been found in most biological fluids, such as blood, urine and semen. Because of these capacities, exosomes are considered to have a role in intercellular communication and to have a potential use as biomarkers or therapeutic tools. In this study, the role of the proteins Rab3D and Rab3B in exosome release was investigated in the human epithelial prostate cancer (PCa) cell line PC-3. Rab3 proteins have previously been linked with cellular secretion, and specifically Rab3D and Rab3B have been found to be enriched in urinary exosomes from PCa patients compared to healthy males. The role of Rab3D and Rab3B was investigated by depleting these proteins from cells by siRNA transfection. The results of this study indicate that depletion of Rab3D or Rab3B may increase exosome secretion, but further experiments are required to validate these results.