Exocytosis from nearly all cell forms including dendritic cells, lymphocytes, and tumor cells , . Exosomes are identified in virtually all physiological fluids including urine, plasma, sn-Glycerol 3-phosphate lithium saliva, semen and breast milk since their smaller size allows them to travel freely across tissue spaces and in the circulatory method . Furthermore, due to the fact exosomes bear the molecular signatures of your cell of origin, they’ve been broadly studied for the development of biomarkers , . Nonetheless, many current studies have demonstrated that exosomes may possibly act as mediators of intercellular communications affecting a variety of physiological and pathophysiological processes . Intercellular communications mediated by exosomes are mostly accomplished by means of either one particular or numerous mechanisms of exosome-target cell interactions. Exosomes happen to be shown to interact with target cells by certain receptor-ligand engagements sometimes major to their uptake by target cells when simultaneously triggering particular intracellular signal cascades (i.e., by means of juxtacrine signaling), which normally leads to alterations of gene expression in these target cells , . Other mechanisms of exosome-target cell interactions include their uptake either by phagocytosis or fusion of exosomal membranes with target cell plasma membranes . Irrespective of the involved mechanisms, exosomal cargo has been shown to become delivered into cytosolic compartments and usually also ends up within the nuclei of target cells . In the context of tumor development, exosome-mediated signaling has been shown to promote tumor progression by way of communications in between the tumor and its surrounding stroma , activation of proliferative and angiogenic pathways , initiation of premetastatic web pages , , and suppression in the immune-surveillance machinery . In breast cancers, tumor secreted exosomes have already been shown to facilitate tumor progression and metastasis by affecting cancer cell adhesion and spreading , transfer of phenotypic traits to secondary cells , converting adipose tissue derived mesenchymal stem cells into myofibroblast like cells , and by inhibiting differentiation of bone marrow dendritic cells . In addition to tumor secreted exosomes, these secreted by standard cells of your TME have also been shown to facilitate tumor development and metastasis by acting upon the breast cancer cells , . Having said that, totally unknown will be the effects of breast cancer cell secreted exosomes on the regular mammary epithelial cells which are one of many essential members of the ductal microenvironment and are also found in TME of invasive disease. In this study, we determined how breast cancer cell released exosomes manipulate human key mammary epithelial cells (HMECs) to facilitate tumor development. We show that exosomes released from breast cancer cells are taken up by HMECs and exosome-HMEC interactions outcomes in ROS production. ROS induces autophagy, DNA damage response (DDR), phosphorylation of p53 at serine 15 and stabilization of p53 in HMECs.PLOS One | plosone.orgTreatment of HMECs with the ROS inhibitor N-acetyl-L-cysteine (NAC) not merely abrogates ROS production for the duration of exosomeHMEC interaction, but additionally abrogates autophagy, DDR and phosphorylation of p53. Functionally, we show that spent culture media from exosome induced autophagic HMECs can stimulate growth of distinctive breast cancer cell lines, indicating the release of tumor advertising things by autophagic HMECs.