Browsing by Subject "ekstrasellulaarivesikkeli"

Extracellular vesicles are cell-derived vesicles which consist of two lipid layers. Extracellular vesicles involve in intercellular communication, maintaining of homeostase and development of pathophysiological states in human body. Extracellular vesicles are promising biomarkers and drug carriers in future. The aim of this study was to develop a method based on time resolved fluorescence microscopy and autologous extracellular vesicles labelled with environmentally sensitive fluorescent probes for studying the distribution of mitose-inhibitor paclitaxel in prostate cancer cells (PC-3) carried by extracellular vesicles. The efficacy of paclitaxel loaded extracellular vesicles was compared to synthetic liposomes. The two subpopulations of extracellular vesicles, exosome -and microvesicle-enriched, were isolated from the PC-3 cell media by differential ultracentrifugation. The size distribution and particle concentration of extracellular vesicles was determined by nanoparticle tracking analysis. DSPC-Cholesterol liposomes were prepared by reverse-phase evaporation method and the size distribution of the liposomes was determined by dynamic laser diffraction and nanoparticle tracking analysis. Paclitaxel was loaded into the liposomes in hydration phase and into the extracellular vesicles by incubating vesicles and paclitaxel. Unbound paclitaxel was removed from samples by ultracentrifugation. The the dose-dependent sytotoxicity of paclitaxel loaded extracellular vesicles and liposomes was evaluated with Alamar Blue viability assay. The release and distribution of paclitaxel from extracellular vesicles in living PC-3 cells was investigated by confocal microscopy and time-resolved fluorescence microscopy. The exosomes had approximately 50 nm smaller diameter than microvesicles and exosome particle concentrations were significantly higher compared to microvesicles. According to viability assays conducted with wide range of concentrations, paclitaxel loaded in microvesicles were slightly more effective than paclitaxel loaded in exosomes. The time-resolved fluorescence microscopy was useful method for investigating the release and distribution of extracellular vesicle bound paclitaxel, since we succesfully detected changes in Paclitaxel-OregonGreen fluorescence lifetime in different phases of the drug delivery process. With confocal microscopy we detected that paclitaxel loaded extracellular vesicles were already uptaken inside the cells after two hours of incubation and after few hours, paclitaxel was detected in microtubules of PC-3 cells and killed PC-3 cells. Extracellular vesicles may improve the accumulation of paclitaxel into tumor cells thus preventing the side-effects of paclitaxel. Nevertheless, PC-3 cell derived extracellular vesicles have ability to increase the PC-3 cell viability, which limits their potential use as drug carrier due to safety issues. In addition, extracellular vesicles characterization and isolation methods lack standardization and the isolation of exosomes and microvesicles is impossible due to this fact. Extracellular vesicles involvement in physiological and pathophysiological states should be investigated throughoutly and their safety as drug carriers should be examined both in animal and human.