Regulation of exosomes released from normal ovarian epithelial cells and ovarian cancer cells.

As important cell to cell communicator, exosomes carry a range of bioactive molecules which can significantly influence phenotype of recipient cells. Inhibiting or removing cancer cell-derived exosomes are of therapeutic interest. However, regulation of secretion and release mechanism of exosomes is still unclear. To explore the regulation of exosomes released from normal ovarian epithelial cells and ovarian cancer cells, a normal ovarian epithelial cell line and three ovarian epithelial cancer cell lines were utilized to investigate their exosomes' release and regulation. A cervical cancer cell SiHa was used for identifying tissue specificity. NanoSight NS500 was used to quantify exosome numbers. Exosomes were labeled and observed by confocal microscopy to investigate their interaction with different ovarian cell lines. Exosomes released from normal or ovarian cancer cells were regulated by the extracellular exosomes. Exosome release was inhibited with the extracellular exosome concentration increase. Exosomes from normal ovarian cell and cervical cancer cell also inhibited ovarian cancer cell-derived exosome release, and there was no tissue specificity. PKH26-labeled exosomes from normal ovarian cell and cervical cancer cell were uptaken by ovarian cancer cells. Release of exosomes from ovarian cancer cell is regulated by a feedback mechanism without tissue specificity. This may provide a therapeutic approach to control the release of exosomes from ovarian cancer cells.