Circulating exosomes potentiate tumor malignant properties in a mouse model of chronic sleep fragmentation

// Abdelnaby Khalyfa 1 , Isaac Almendros 1, 4 , Alex Gileles-Hillel 1 , Mahzad Akbarpour 1 , Wojciech Trzepizur 1 , Babak Mokhlesi 2 , Lei Huang 3 , Jorge Andrade 3 , Ramon Farré 4 , David Gozal 1 1 Section of Pediatric Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, The University of Chicago, Chicago, IL, USA 2 Department of Medicine, Section of Pulmonary and Critical Care, Sleep Disorders Center, The University of Chicago, Chicago, IL, USA 3 Center for Research Informatics, The University of Chicago, Chicago, IL, USA 4 Unitat de Biofísica i Bioenginyeria, Facultat de Medicina, Universitat de Barcelona-Institut Investigacions Biomediques August Pi Sunyer-CIBER Enfermedades Respiratorias, Barcelona, Spain Correspondence to: David Gozal, email: dgozal@uchicago.edu Keywords: sleep fragmentation, obstructive sleep apnea, tumors, microenvironment, cancer biology Received: April 16, 2016 Accepted: June 30, 2016 Published: July 13, 2016 ABSTRACT Background: Chronic sleep fragmentation (SF) increases cancer aggressiveness in mice. Exosomes exhibit pleiotropic biological functions, including immune regulatory functions, antigen presentation, intracellular communication and inter-cellular transfer of RNA and proteins. We hypothesized that SF-induced alterations in biosynthesis and cargo of plasma exosomes may affect tumor cell properties. Results: SF-derived exosomes increased tumor cell proliferation (~13%), migration (~2.3-fold) and extravasation (~10%) when compared to exosomes from SC-exposed mice. Similarly, Pre exosomes from OSA patients significantly enhanced proliferation and migration of human adenocarcinoma cells compared to Post . SF-exosomal cargo revealed 3 discrete differentially expressed miRNAs, and exploration of potential mRNA targets in TC1 tumor cells uncovered 132 differentially expressed genes that encode for multiple cancer-related pathways. Methods: Plasma-derived exosomes from C57/B6 mice exposed to 6 wks of SF or sleep control (SC), and from adult human patients with obstructive sleep apnea (OSA) before ( Pre ) and after adherent treatment for 6 wks ( Post ) were co-cultured with mouse lung TC1 or human adenocarcinoma tumor cell lines, respectively. Proliferation, migration, invasion, endothelial barrier integrity and extravasation assays of tumor cells were performed. Plasma mouse exosomal miRNAs were profiled with arrays, and transcriptomic assessments of TC1 cells exposed to SF or SC exosomes were conducted to identify gene targets. Conclusions: Chronic SF induces alterations in exosomal miRNA cargo that alter the biological properties of TC1 lung tumor cells to enhance their proliferative, migratory and extravasation properties, and similar findings occur in OSA patients, in whom SF is a constitutive component of their sleep disorder. Thus, exosomes could participate, at least in part, in the adverse cancer outcomes observed in OSA.