RESUMO
The transfer of exosomes containing both genetic and protein materials is necessary for the control of the cancer cell microenvironment to promote tumor angiogenesis. The nature and function of proteins found in the exosomal cargo, and the mechanism of their action in membrane transport and related signaling events are not clearly understood. In this study, we demonstrate, in human lung cancer A549 cells, that the exosome release mechanism is closely linked to the multifaceted receptor sortilin (also called neurotensin receptor 3). Sortilin is already known to be important for cancer cell function. Here, we report for the first time its role in the assembly of a tyrosine kinase complex and subsequent exosome release. This new complex (termed the TES complex) is found in exosomes and results in the linkage of the two tyrosine kinase receptors TrkB (also known as NTRK2) and EGFR with sortilin. Using in vitro models, we demonstrate that this sortilin-containing complex exhibits a control on endothelial cells and angiogenesis activation through exosome transfer.
Assuntos
Proteínas Adaptadoras de Transporte Vesicular/metabolismo , Receptores ErbB/metabolismo , Exossomos/metabolismo , Glicoproteínas de Membrana/metabolismo , Proteínas Tirosina Quinases/metabolismo , Proteínas Adaptadoras de Transporte Vesicular/genética , Linhagem Celular Tumoral , Movimento Celular , Células Endoteliais/enzimologia , Células Endoteliais/metabolismo , Receptores ErbB/genética , Exossomos/enzimologia , Humanos , Glicoproteínas de Membrana/genética , Ligação Proteica , Proteínas Tirosina Quinases/genética , Receptor trkB , Transdução de SinaisRESUMO
The neurotensin receptor-3 also known as sortilin was the first member of the small family of vacuolar protein sorting 10 protein domain (Vps10p) discovered two decades ago in the human brain. The expression of sortilin is not confined to the nervous system but sortilin is ubiquitously expressed in many tissues. Sortilin has multiple roles in the cell as a receptor or a co-receptor, in protein transport of many interacting partners to the plasma membrane, to the endocytic pathway and to the lysosomes for protein degradation. Sortilin could be considered as the cells own shuttle system. In many human diseases including neurological diseases and cancer, sortilin expression has been shown to be deregulated. In addition, some studies have highlighted that the extracellular domain of sortilin is shedded into the culture media by an unknown mechanism. Sortilin can be released in exosomes and appears to control some mechanisms of exosome biogenesis. In lung cancer cells, sortilin can associate with two receptor tyrosine kinase receptors called the TES complex found in exosomes. Exosomes carrying the TES complex can convey a microenvironment control through the activation of ErbB signaling pathways and the release of angiogenic factors. Deregulation of sortilin function is now emerging to be implicated in four major human diseases- cardiovascular disease, Type 2 diabetes mellitus, Alzheimer disease and cancer.
RESUMO
Chronic necrotizing or semi-invasive aspergillosis represents a disease commonly occurred in patients with mild immunodeficiency. We report a case of chronic necrotizing pulmonary aspergillosis in immunocompetent patient without underlying disease. The discovery of the disease was made accidentally, by finding a nodular opacity on a routine chest X-ray. The diagnostic was confirmed by pathological and bacteriological examination. With specific antifungal treatment, no complete eradication was obtained and the patient has a slow evolution with many relapses.