Strukturelle und funktionelle Charakterisierung von Exosomen aus Prostatakarzinomzellen Prostatakrebs Zellkommunikation Vesikel Tumorwachstum Exosomen prostate cancer exosomes microenvironment protein uptake Exosomes are small vesicles with a diameter between 50–150nm which are secreted into the extracellular space. Emerging evidence shows that they may serve as vehicles for signal molecules in order to modulate target cells. As such exosomes may play a pivotal role in tumor progression by influencing the remodeling of the tumor environment and modulating tumor associated non malignant cells. A better understanding of composition and function of these nanovesicles could lead to diagnostic and therapeutic advances in the treatment of cancer. Protein and mRNA composition as well as functions of prostate cancer cell derived exosomes were analyzed within this work. Exosomes were prepared from prostate cancer cell lines LNCaP PC 3 and PC3 HSP27 via ultracentrifugation. Validation of exosomal enrichment and characterization of morphology were conducted by means of dynamic light scattering and electron microscopy. Exosomal mRNA and protein composition were analyzed by DNA microarrays and gel electrophoresis as well as mass spectrometry. Effects of tumor exosomes on non malignant target cells were studied by means of cell survival assays and cytotxicity assays. Using the SILAC method the potential uptake of exosomal human proteins into canine cells and de novo synthesis of proteins through transferred exosomal mRNA was analyzed in MDCK cells via mass spectrometry. Analysis of exosomal composition showed that these vesicles are highly enriched in membrane proteins the packaging of ...